I did German at Uni and School. Watatank is correct. Listen to as much German as you can. Try and watch German shows on SBS, catch the German news on SBS radio if you can, or get someone to tape it for you. You can stream it off the internet as well. That can be good to do, because then you can listen to it over and over and get a feel for what they are saying.
The neat thing about listening to the radio news is: 1. listen to it in English on another radio station and then 2. listen to it in German. You know what they are talking about and are more likely to understand the words that are unfamiliar.
Also, catch the Deutsche Welle news on SBS TV if you can. They speak fast, but again, if you know the news stories you will be better off.
In terms of speaking, don't try and translate in your head, ie don't think about what you want to say in English and then try and say it in German. Just start talking German, use the words you think fit and just move on. Don't dwell on mistakes. (I once said I had missed the bus but in such a way that it meant I was missing it
Think of the simplest way to say something - the KISS formula (keep it simple stupid). THIS IS KEY!
Certainly, learn some key phrases for particular circumstances, especially "Nach meiner Meinung" und so weiter. To get a good set of these, get a phrase book for travellers, they are really great for that sort of thing.
AND PRACTICE! Practice with your friends. Say, "for the next half and hour we are only going to talk in German" and do it. It is hard and you will find there are a lot of things you won't know how to say BUT you are allowed to use a dictionary. It can be a lot of fun.
Hope that helps.
Und auch kannst du hier mit anderem auf Deutsch reden. Dass macht auch Spaß.
Viel Glück!
