This topic really didn't deserve a college paper. For new players who don't know what the fuck to do, here are some key things to remember:
1. Realize that you are a liability and a burden on your team.
2. Perfect practice makes perfect.
3. Play with retards at first, and build up from there. You'll be able to gauge where you're at skillwise.
4. Repetition, repetition, repetition. This one relates to number 2, but it's different.
5. Watch streams, listen to any advice from people who seem to have an idea of what to do and don't hesitate to ask questions. People like when you give them the time of day. It makes them feel special.
6. Play a class that you like the most out of all the other classes, and stick to it.