This is mainly a guide, and a way of helping you guys, not get banned as much, and have fun hacking.
Do's
Always, and I mean always, cipher a hack before using it.
Always test hacks on a new account, and if you aren't banned on the test account, you can use it on your main account if you really want to risk it all.
Use an injector that you know will work, I use PerX by xKickAss.
Don'ts
Never use a patched hack, it will not work, it's called a patched hack for a reason.
(Obviously) Never use an injector that is detected, as you might get banned since Nexon's Anti-Hack will pick it up and ban you.
If you don't want to be banned, try not to use hacks like opk, rapid fire, no recoil, hacks that'll pretty much give you away.
Extra Stuff:
The Combat Arms process name is Engine
Some injectors require you to put .exe after the process name to correctly inject a hack, for example, if the process of a game was Example.exe you'd put Example.exe in the process name.