Check out a post I replied to
here first - saves me having to type it out all over again!
I can actually give specific advise for German though, so here it is! I did AS and A2 German with WJEC.
If you're planning on taking German to A2 level, no matter what you get at AS, retake both units. You naturally get better at a language, so it just makes sense. I barely scraped a D at AS German, but I resat it this year along with my A2 exams (and no revision!) and got B (a few UMS off an A).
For the speaking exam, you need to make sure you keep talking. So if you're unsure whether or not what you're saying is correct, it's better to say something than nothing at all. You wont lose marks for accuracy (unless it's a very basic and obvious mistake that you really shouldn't have made), and you'll possibly gain marks for keeping the conversation going.
To help practice your speaking, always make an effort to talk in German during class and to anyone who can talk German fluently. So it might be worth staying behind/going to a lesson early to chat with your teacher in German about nothing in particular. You can also find native speakers online who may be willing to talk over skype - a good place to start for this would be
/r/German. In fact, /r/German is a good resource overall to help with everything, and it's a good place to ask questions too.
Another good idea is to watch German films (with English subtitles if you prefer) to see how German is used when it's spoken. Personally I'd recommend
Goobye Lenin! as it's easy enough to follow. If you want to practice listening comprehension then flick on the German subtitles so you can read what is being said. Don't worry if you don't completely understand it, sometimes the subitles wont match exactly what is being said (it's the same in English and almost every other language ever), just try and match the words and the sounds.
To put your listening comprehension to the test, check out the Top Thema on
Deutsche Welle. You listen to a short news story (with a transcript underneath but try not to look at that) and then have to answer some questions based on what you heard/read.
Any other questions? Just ask!