For me this is wat i wuld do:
com: 6 singularity, 6 gravity well, 6 on all buffs except growing rage, and rest on graviton slam
first use graviton slam to slow enemies, gravity well to pull and then use singulairty to blast away.
Tip: always use the armour buff b4 using gravity well.

eng: 6 empathy, 1 rev, 6 transference, 6 leech, 6 protection, 6 force field, 6 on sonic boom and rest on pain.
buff up with protection and empathy, use pain, sonic boom and then transference. Keep leech as a emergency if healing is too slow.

op: use apollo's guide, found on forums.
use amplified pain and the fire move, lurch, switch opponents and used root nueral shock and lurch. Re
Tip: for kills, i recommend solo biosphere2. Turn left and complete first room than rmk
and if u r with a group, dont try tank unless u hav a unreliable connection or u may die easily

If u want a short tutorial, pm these characters:
IGN: Doggies(com), Manofmight(eng) and Hellcurse(op). I usually on doggies as im trying to cap but if u need help, just pm me and ill come with my eng
ENJOY