This thread has been created to share the collective knowledge that exists among the higher-tier players of Heroes of Newerth. For example me or, well, just me. It is not designed as a specific guide for each hero, but rather a generalised guide of tips and tricks that can be learned and applied from experience, practice and patience. This is a work-in-progress, and will be worked on as often as I can. In addition, it will be updated when I can, providing data for new and updated content as it arrives. The content in this article is based off my experiences from Mid-Tier games with some of the best players (Jiggle_Billy, AngryTestie, Nazghull), watching tournament games (FnaticMSI, Frenetic Array, Five, DWi, Lion, VICE) as well as downloading and studying replays from the world's best players (Chu, N0tail, Trixi, Nova_, Freshpro, Slickz, Moonmeander).
Please note that this isn't a chance for me to boast about who I've played with or what I've watched, but rather I feel it is necessary to show at least some form of credentials to prove this article's authenticity and accuracy. I do not hate boasting about my skills in HoN, Arun would know, but recognizing that I did not collect these tricks all alone is necessary. Also please note that there is no real way to organize such an extensive list, so be prepared for a wall of text - I will endeavour to make it as painless and pretty as possible though. So with that out of the way, let's fucking do this.
Basic Tips
General:
To maximise the effectiveness of a bottle/health potion or natural regen, switch your Steam Boots to Agility. This lowers both your maximum health and mana pools, meaning when you switch back your current mana % is raised with it. Dropping any items that give bonus health/mana can also help a lot, just make sure they're safe and won't be stolen!
Attacking an enemy hero in lane causes the opposing wave to 'aggro', this can be used to your advantage to manipulate the wave where you want.
Standing on higher ground not only gives 25% evasion, but also gives sight on units below your level. The opposite applies for units on the ground, they can't see what you're doing.
You can deny a hero if they have a damage-over-time effect (excluding Jester's curse), this can deny the enemy upwards of 500 gold.
There are many spells that Disjoint, dodging any projectiles (spells and attacks) currently in the air, teleporting, invisibility and invulnerability are all examples of Disjoints. (Although invisibility and invulnerable are not 'true' disjoints).
Tablet of Command can be used to push allies (or enemies) out of AoE Disables such as Chronos/Tempest/Poly ultimates.
Sol's Bulwark can be toggled to provide extra armour when being chased down, the same concept applies for Steamboots.
Daemonic Breastplate affects Towers as well, making it a powerful pushing/defensive item.
Logger's Hatchet doesn't take your combat type into account, due to this - attacks against Seige units will deal regular damage, instead of reduced damage.
Low mana cost abilities such as Dark Lady's Taint Soul can be used to effectively harass and last-hit while being pressured.
Abilities that hit an area work differently than abilities that select every unit within an area. Examples of this are Pyromancer's stun versus Valkyrie's Call. Abilities that select targets generally do not hit invisible/fogged targets.
Always carry a Homecoming Stone - not only does it help with map control, but it can be used to escape ganks against heroes that have no stuns, or heroes that have already used them.
If you pick up an illusion rune, try baiting enemy spells with it by controlling one illusion as if it were your actual hero. (Moving erratically, trying to last hit/juke etc).
When bottling an invis rune, you can use 1 charge of your bottle during the fade time of the invisibility without breaking it.
You can use Runes of the Blight or Logger's Hatchet to cut down trees to stack creep camps, or AoE spells to hit the creeps directly.
Logger's Hatchet doesn't actually count as an attack, due to this - it cannot miss uphill, and deals full damage to Seige units.
Pets and illusions are a great way to destroy gadgets that have a set amount of attacks such as Wards, Pharaoh Mummies and Arachna's ultimate.
You can buy Wards, Health Potions and Mana Potions from the Observatory, and can finish full recipes in the Outpost such as Steamboots, Shaman's Headdress and Iron Shield.
There are many hidden paths through trees which become available when cutting down key trees with a Hatchet or Runes, and can be used to escape or get behind enemies.
Hero Specific:
Bubbles with a Portal Key can use a level 4 Take Cover to reset the damaged cooldown on his PK, allowing him to port away safely.
Any hero can teleport to their pets if they have a Post Haste; a prime example of this is Tundra teleporting to Shiver to gank.
Vindicator is a solid counter to combo-dependant heroes such as Pebbles, Bubbles and Chipper.
Gladiator's Flagellation can be used to 'snipe' low health heroes by hitting the creep while facing the hero's direction. This also works for invisible heroes. When used to deny, it doesn't go on cooldown.
Myrmidon's Wave Form/Dark Lady's Charging Strikes etc can be used to escape pathing blockers such as Pharaoh's Mummy Wall, Behemoth's Fissure and Empath's Wall. These spells do not go through them, but will find a way round no matter how perfect the block is.
Soulstealer's Ultimate hits regardless of vision, and can be used to take out those pesky jukers.
Engineer's Mines/Emerald Warden's traps etc can be used to block neutral camps.
Tundra can have a 'never-miss' Piercing Shards by throwing them, then charging the target hero - the shards will return and hit the target.
Demented Shaman's cloak has a travel-time, meaning your ally can die with it mid-air and it will still go on cooldown/cost mana.
To maximize Demented Shaman's heal dissipation, stand behind your target with allies in front, this enclosure deals ridiculous damage early on when you heal.
Accursed/Devourer etc can deny themselves with their masochistic abilities. (Spells that damage themselves).
Witch Slayer, Pyromancer and Plague Rider's ultimates cannot be disjointed, but can be blocked by invulnerability.
Pharaoh's Mummy Wall can be used to block paths while escaping; cast it in a choke-point and destroy a mummy to get out.
There are many abilities that damage towers, such as Flint's Flare and Pebbles' Chuck.
Thunderbringer's Lightning Blast and Lightning Storm abilities reveal invisible units around the unit that is hit, a well-aimed blast can reveal that low-health Nomad or Scout!
Tremble's Dark Swarm ability can be used as a powerful defensive mechanic when fleeing.
Monkey King can vault over his rock summoned by Wan Jin Slam, this is considered a building and doubles the distance travelled.
Balphagore's Regurgitate ability creates corpses in front of him, and can be used as an effective burst heal when being chased.
Dampeer can use his ultimate on creeps to generate essences or to provide a quick self-heal.
Nighthound can Pounce to the Runes, as well as allied units.
Swiftblade and Predator's Magic Immunities can give you a safe way to escape from ganks against nukers and stunners.
Attacking a creep and applying Boom Dust while your projectile is mid-air as Bombadier provides a (nearly) fool-proof way to last hit and harass melee heroes at the same time!
Sand Wraith's Curse and Ra's Meteor give them the ability to go through all terrain and units, if in trouble you can use these abilities to essentially get off the edge of the map, make sure you're carrying a Homecoming stone!
Intermediate Tips
General:
In some situations, purchasing armour is more beneficial for survivability than purchasing bonus health items. This is called boosting your Effective Hit Points (EHP) and applies to both Magic Armour and Armour for their respective damage.
You can use Ring of Sorcery and Astrolabe on invulnerable allies, restoring an ally in a Cyclone may give him enough mana to nuke his opponent down, or enough health to make his getaway.
Learn to 'fake' your abilities - Valkyrie, Devourer and Pyromancer all have abilities that can be cancelled, meaning you don't waste your skillshot if you know it's going to miss. Experiment with other heroes to see what other spells you can cancel! (Some are really annoying for your opponents!)
Mid heroes can purchase a hatchet or 4x Minor Totems. While risky, it means you can get a much faster Bottle.
You can manipulate creep waves with pets or illusions, do this by sending the pet ahead of you to pull the wave, then redirect it to neutral camps so you can push freely.
Insanitarius can be toggled on before a damaging spell hits, if toggled off straight after, you won't have lost any health from the spell.
Shift + Click commands ahead of time, this can be applied to Rune-Whoring, eating Trees or combo spells like Devourer's Ultimate + Autoattack. It is done by issuing a command, then while that command is being called, holding Shift + issuing another command.
Frostfield Plate provides 2 seconds of Clearvision in a huge area, use this to catch people trying to juke you.
Puzzlebox Level 3 provides True Sight in a large area, use this to catch invisible heroes or to counterward.
Heroes with channeling abilities can use items such as Shrunken Head and Assassin's Shroud without breaking the channel, this also works for Toggle-Abilities such as Devourer's Decay.
Enemy Legionnaires can be severely hindered by placing a ward on the Yellow Neutral camp to block spawns there.
There is a tree above Kongor that the Hellbourne Middle player may cut down to gain access to the Observatory, allowing him to purchase Wards and Health/Mana potions.
Once stacked, you can cut down the tree above the Legion Forest Camp (the one used for pulls) and pull them up towards the camp straight above them. This allows you to fight both stacks at once with any powerful jungler such as Legionnaire, or with the support of teammates.
Hero Specific:
Succubus' Mesmerize provides split-second invulnerability, which can be used to effectively protect against enemy spells such as Pebbles' combo and Flints ultimate.
Gauntlet's Grapple can be used over creeps. And his Infernal Instability gives a moderate movespeed boost, which is useful for chasing or escaping.
Gladiator's Showdown can be used to line up a perfect Pitfall, as well as a Disjoint.
Flint's Flare (as well as other abilities) provides Clearvision where it lands, this can be used to give sight of a low-health enemy and give you enough time to unload an ultimate to finish them off.
Accursed's Cauterize damages him, so it can be used to give a burst of health during his ultimate. His shield also dispels debuffs and can be used to stop Succubus' ult on the target!
Ra's nukes both destroy trees, removing the cover of jukers.
Pharaoh's Hellfire and Valkyrie's Call of the Valkyrie abilities do not hit invisible units, but Torturor's Impalement does. Impalement also continues to deal damage even if Torturor dies.
Deadwood's ultimate can be cancelled, useful for baiting things like Nomad's ultimate.
Devourer's ultimate can be used to provide an extra boost of health when getting chased, it also works on neutrals and lane creeps.
Both Shadowblades charge and ultimate can be used on himself. His Soul's Sight also gives clearvision.
Use Tremble's mounds to destroy trees and reveal jukers, this also applies to other spells as well.
Magebane's Ultimate mini-stuns, and can be used to stop Homecoming Stones and other channeling spells. This also applies to Plague Rider's Ultimate.
Andromeda and Pharaoh can block Neutral Spawns with Aurora/Tormented Soul, respectively.
Aluna can stack several Neutral camps at once with her ultimate-boosted Power Throw.
Pharaoh can activate Wall of Mummies next to a cliff, then deny one of the mummies sitting on the cliff itself. This allows him to run up and down cliffs to chase or escape. The same works for Engineer's Keg (cast it to knock yourself up or down cliffs).
Parasite can Infest his own minions summoned by Puzzlebox. Hopping inside a low-health mauler can deal massive damage to the unit that kills it, and the wizard has high attack damage and a speed aura/mana burn. He can also infest Ophelia's creeps, and those Dominated with a Whispering Helm.
You can issue commands to Poly's wards, telling them who to attack in a teamfight, they can also deny and be used to last hit towers under pressure.
Advanced Tips
General:
Pets can be used to dispel on-damaged effects, these include Succubus' Mesmerize and Gauntlet's ultimate.
Many stuns can be used to prevent other stuns, depending on their cast time. For example, Pestilence can prevent Behemoth using fissure due to his low cast time.
Spells that give invulnerability (Barrel Roll, Mesmerize, Stormspirit, Take Cover) can be used to dodge Rampage's Charge, Engineer's Mines and other abilities.
Hero Specific:
Maliken's ultimate gives a massive armour boost when used, and can be effectively utilized as protection against an attack that would otherwise kill you.
Tundra (and other heroes) can use their pets to sweep for Engineer's Mines and Warden's Traps.
Pets and illusions can be used to deny the rune.
In most scenarios, it is more effective to deny a Melee creep from the first wave when using Plague Rider. They give more experience and have significantly more health for pushing. This can also be used to deny the first creep in Middle to help your team mate win his lane.
Devourer's Decay can be toggled on/off quickly to provide a lingering AoE slow without dealing significant damage to Devourer.
Slither can use his wards to block pathing/slow enemies when placed at their feet, make sure to take latency into account and aim accordingly!
Ophelia can use her nuke to teleport allies to safety in dire situations, remember that it teleports her creeps instantly.
Nomad can use his ultimate during Ra's respawn time, because he explodes when he comes back, the ultimate procs and goes off. This makes Nomad an even stronger counter to Ra.
Final Notes
Remember that a lot of these tips will require hours of practice and patience, and some will be easier to grasp than others. Feel free to comment or PM me if you think something is missing from this list, or if you disagree with the content. Feedback is appreciated, but trolls and flaming will be ignored. Thanks for reading, and good luck! If anybody feels like going 1 v 1 with me, VM me so we can arrange the time.