As Zor2 said, ignore the insults.
I want you to know some things:
About Marines:As Zor2 said (again...

), follow waypoints and all orders of your commander, and stay with your mates. But being with your mates is not only for you to stay alive... Just watch what your mates do, to be more independant in the future. The commander is very busy, and maybe he doesn't see that you need medpack or RT. Don't hesitate to ask him them...
And of course, go commander only when you know what you do !
About Aliens:Remember to tell your mates what you are doing in the game. For example, at the beginning of the game, say "saving for hive", "saving for fade", "RT", etc. If you are not really good, go gorge, and build chambers or RT. Ask your mates what chamber they want, but they certainly won't answer... So wait a little bit, and then build MC: generally it's the chamber the people prefers. Practise your lifeforms in CO, or when your team is winning -or when you have plenty of ressources-.
Remember...Look at your minimap ! When structures are being attacked, just tell your mates "GO 'position', 'structure' being attacked !"
Don't hesitate to join a community, or a team which doesn't expect good skill. Your teammates would be able to answer your questions, help you, or just make you getting a name in NScommunity

Never be desperate, Natural Selection is so good !!!