Too start with, you are flying the ship too aggressively and leaving your shields on too much. The Dominator's biggest guns are in fixed forward mounts, it has very limited coverage for its rear arcs, and it turns incredibly slowly. These traits mean that most builds will be standoffish rather than true brawlers, and you want to be planning your positioning well in advance to make sure you don't get outflanked. Burn drive is a very powerful tool for mobility, but it will also happily give you all the rope you need to hang yourself if you use it to get into a situation you can't get back out of.
Your shield is very inefficient and most comparable ships will have better flux stats than you, so you aren't well-suited to winning flux wars with shields. Stack armor and take advantage of excellent ballistic PD like Dual Flak to keep missiles in check even under flux pressure, and only engage your shields when you're about to take big hits of HE damage that you can't otherwise avoid. This lets you dump all your flux into damage and overwhelm opponents even with nominally superior flux statistics to yours. This is also one of the better times to use burn drive; if you have an opponent fluxed out and they're backing off to breathe, burn drive can force the engagement long enough to finish them off (and you had best believe that shield ships will not last long under the guns of a Dominator if they're capped out on flux).
You want to be actively turning your shields off if you're about to hits from light kinetics like Needlers that don't have any HE damage backing them up; they'll barely scratch the paint on your armor, while taking a huge hit of hard flux will cut into your damage output and might leave you stuck out if you need to throw your shields up to catch a bombing run.
In general, try to work with your fleet, because the Dominator is an easy ship to get mobbed in.
