Improving English language skills

I'm a native German Speaker with English as my second language. I'd like to improve my skills in the English language but don't know how to. What I currently do is watching English movies and writing in English forums such as 4chan. The problem is, by watching movies I'm just a passive actor, it's no practice. Writing in forums is, but I get no feedback (what's important to improve skills, I think) and/or write simple sentences only.

What do? Maybe I should join a community full of grammar nazis, giving me no room for errors without being admonished, but does such a place exist?

>>1
You might want to try out Lang-8.com, it's a website where people can post journal entries in the language they're learning, and native speakers of that language can correct your grammar/spelling mistakes and usually give good explanations. Good luck.