Level 41 Shadow here. I did find that early on in the levels you're at tanking was much harder. Solo quests against elites had me throwing my hands up cause I'd get an enemy down to a sliver of health and he'd somehow beat me still. I used and continue to use Theran ALOT for healing and stunning enemies with his holo chick. I use stun every time it cools down if that fight is long enough, I use endurance stims on every boss, combat stance, guard, call upon force or whatever its called for Consulars, right as my health starts going down and a Med pack right after. I rotate between project, telekinetic throw, double strike, mind snap and attack only when the others are cooling down.
At this point I've been fighting two elites at once if I CC the other and bring the other down in health considerably so that when one comes out of CC I'm almost done with one and can focus on the other. Hope this helps or you find a strategy that works for you.