Probably that's the reason I still have problem using the right tenses while speaking, especially simple past, present perfect and the belonging progressive forms...
"belonging progressive forms?" Could it be you mean "respective" (or "corresponding")?
But anyway, I think it does matter where exactly you are (talking about) "in the US"... One good (or bad?
) thing about living in the South... nobody cares about unimportant things like grammar and such (famous quote
- "...she loves him in spite of his ways she
don't understand..."). After all, it's all one big family down here (a.k.a. "they said they were married but they're really brother and sister"
), so everybody knows what you mean regardless of how you say it - and most of the time, they wouldn't even know there's anything wrong with it anyway... rather the contrary - speak "overly correct", and you'll most certainly give yourself away
. On the other hand, I don't doubt that in parts of the heavily German-influenced North you might want to take a little more effort regarding these matters if you don't want to "raise some eyebrows"...
This is probably the reason I have a much more American than German accent
Sorry, but there's no such thing as
an "American accent"...
Back to the question of "how do you practice"...
When I was at university, they had a thing called an "English Roundtable" - open to everyone interested, a group of people consisting of native and non-native speakers getting together one night a week at a local pub to talk about "God and the World", so to speak. That, to me, would be the absolute best way to "practice" at home - you can read, watch, and listen all that you want, but speaking (other than the "repeat after me"-exercise) is totally different thing. Although I gotta admit I myself always happened to find an excuse to "maybe go the next time"...
Other than that, the usual suspects - English books/papers/movies/news/correspondence...