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?

>>2
If you think my English is awful, you certainly won't want to hear my pronunciation. But I don't actually care about it, I just write this because I want to make use of every opportunity that allows me to write some English text.

>>3
Agreed.

>>4
Very interesting, that's what I'm looking for. Thanks a lot!