from the guide...

Dual/Tri-Boxing

ANY GROUP WILL WORK! As a duo or a trio, you won't really be running instances, just using the group to minimize downtime and plow through quests. Every class can solo to 70 so every pair or threesome of classes can get to 70 in the same way. PLAY WHAT YOU WANT.

Just choose classes for your alts that are easily macroable (see class overview) and you'll have little problem making a highly effective group. Normal class synergy applies. There are so many combinations that would be effective that it'd be silly to name them all. Just stay away from difficult-to-macro alts and you'll be fine. Here are some of the general tips:

1) Have at most one melee class, make it your main
2) Choose classes that will help minimize downtime (ie if you want a warrior main, choose a shaman over a warlock as a partner)
3) Choose classes that have good synnergy (rogue/druid has great synnergy. Mage/Warlock.. not so much)
4) In my opinion, when in doubt, shaman are awesome. You get ankh and rez!



edit for shitty spelling