All of the numbered points are great and I'm sure this will see dozens of add-on comments, but really, everything in this thread could be summed up by:
1. You're new. There's people playing airsoft that have been doing it way longer than you. Watch how they play, and try to emulate that as best you can. You don't have to be their tag-a-long super-buddy, but stick with a squad you like without getting in their way and learn how they fight. Try to fit in. Eventually, you probably will. When you've learned all you can from these folks, start the process over with a different group that plays even better.