I agree with the reading up about classes that are new to you. You also can run one around solo and figure out the strengths and weaknesses; don't forget to apply the multiboxer rules to what you’re learning.

Also, as for skill ups, I am pretty sure Bliz nerfed the skill ups on low level mobs a while back, or maybe just the servants in Blasted. I used to use the servants around Blasted Lands for skill ups. I forgot about the nerf and ran my pally out and tried this a few weeks ago near the Dark Portal. One minute into the whacking... nothing. I remembered and took off for my other spot, the entrance to SL in Auch. Constant stream of mobs with tanking NPCs. You can multibox skill up there easily.