Well one thing that doesnt appear to have been mentioned is, you cant give yourself bonus through a main/alt, my understanding is they have to be two new characters. This is because you only receive the xp bonus if your "friend" account is nearby, might also have to be grouped; I may be wrong so if I am someone please correct me.

Im also fairly new to dualboxing, started about 3 weeks ago with a fresh Sham/Warr team it is definately tricky to play both classes effectively being seperate. As of now the warrior kills while the sham heals/assist thats about if for the shaman, have keys to drop certain sequences of totems etc if needed but for the most part I charge with warrior and sham follows behind in attack mode to assist. Currently 52 and it was easy the entire way, I probably could of been more efficient by skipping collection quest but it wasnt to bad, but a nuissance of course.

If you havent read the wiki be sure to triple-read it, great info in there I was able to figure it out nearly all on my own...
Few recomendations:
Keyclone, awesome software for dualboxing
Addons:
Jamba

Gluck