First off, I don't run with Mako. I use gault (just got Blizz, will try him). Second, most of the mobs I am fighting are grouped, so I do more AOE than single target.
For single target, try to stick with casted/channeled abilities (unload/powershot) and sparsely sprinkle in the instant ones. Don't forget to use Rapid Shot (spamable cost free ability). The higher your heat gets, the less it regens. So keeping it below 45-60% is key. If you start creeping to high, switch to rapid shots.
Let your companion do damage and heal yourself/them as needed. That is all I can recommend. We are not the fastest content killers in the game, but we can be very durable.
EDIT: Yes, Bodygaurd is a healing tree, but healers have to solo too! Or you DPS folks won't have someone to save your behinds during ops/flashpoints.