hmmm ... well, never leave a major area before there is aboslutely nothing left to do according to your journal, perhaps that's better adviceon the same note, if you're doing a lot of to-ing and fro-ing from one place to another, then i consider them one major area (like the swamp cemetery and old vizima). It's only when you get journal entries like "now I must proceed to... blah, blah, blah" and several of them that you know you are about to leave. so unless you have a specific quest that just can't wait -- that is a show stopper for all the others -- do all the quests you can complete first, then move on.You say you don't know which ones you can complete ? well, you just have to try and see what happens ... when you hit a dead end, it's spelled out in the journal, then you know