Red Orchestra 2 is quite simple actually. You just have to keep playing online and watching documentaries on infantry tactics will help you. Also, focus on surviving instead of killing.
Imagine in your head what would happen if you ran across that street.
Is the street being watched by a sniper? Is there a friendly watching that street? etc etc
You ought to see what happened to me that day. I was surviving for like 12 minutes straight and got killed by my teammate for holding an SVT (I was German)....
http://www.youtube.com/watch?v=Kz0a_QGifPM
About German Infantry tactics from the O.S.S