Try and get your win-ratio up on spirit watch and skyhammer. Those maps are for a lot of people ‘new’ and they don’t have adjusted builds for it.
Make a character with a skyhammer build (Fearlock necro, knockback engi/guardian, etc.). This will allow you to either win the hammer fight most of the time which is very important or hold a node pretty much the entire game.
For spirit watch, make an orb runner. Again, most people don’t have adjusted builds. Tell your team to focus on the capping and you do the orbrunning.
Both these maps are the easiest maps to ‘carry’.
On temple, tell your team the buff-timers and remind them of it every time it’s 30 seconds left. Always go to the buffs yourself, don’t trust your team for this :p (atleast if you’re stuck with bad teams the whole time).
Forest, foefire and kyhlo are a bit harder to carry. I’d say good trebbing on kyhlo can really benefit the team.
Anyway, this is stuff that might help when you’re stuck with really bad teams, not only yours but also theirs. :p As rating settles and you climb the ladder this will become harder.
The leaver problem will fix itself I think. It’s mainly because lots of newbs are joining and either thinking it’s a dueling arena (I’ve heard that twice -.-) or them just trying it once.
