Here's my advices:
- If you have tendence to rage, just use /mute all, it will help a lot you and your team mates because flaming doesn't help at all.
- Play with camera locked. Why? Let's imagine this case, you're top and your enemy is dead and you have half hp. You're looking mid and sundely comes enemy jungler to kill you and you didn't even notice because you were looking mid! In my opinion that distracts a lot.
- Try to farm last hits with Vladimir, it's pretty hard to farm with just lat hits, so it will help a lot.
- Map awareness, be always attention at map.
- Think in all case before you do something. If he has flash, etc.
- Never dive turrents early game. NEVER.
- Use time at your chat, and say like: Teemo Flash, you will know when he used flash and when he will have flash again. It helps a lot.
This is just what i remember for now!