Well the thing with this game versus other mmos I've played is that for the first 30-40 levels you're pretty much solo. So what I did with my Priest is I used a one handed mace and shield because you have to be able to fight some.
As for the sitting and stuff... It really just depends on the party. If they're a good party you shouldn't have to sit too much, but if they're bad sit between healing. A major thing to do is always stock up on Tea from the grocer and as many blue pots and scrolls as you can. Tea is the most essential thing though. Other than that though its all personal preference.