Start out as a bounty hunter, kinda regardless of the legality of the job. Build up my fleet, so that I'm working multiple jobs at once. When I've accumulated enough money, get me a suitable system for a headquarters. (What that will be depends entirely on the game, so dunno yet.) Construct a whopping huge base, preferably one that can be moved if I find a greener pasture. Moving an entire planet from one system to another would be pretty cool. I'd make sure that the operation I set up is not only entirely self-sufficient, but miserably well-defended. You should see the fortresses I build in C&C or Age of Empires.
Anyway, then proceed to do enormous amounts of R&D in order to keep my personal fleet atop the others. My personal flagship would be big, but not that big - more like a Star Destroyer than a Death Star. I'm slightly more of a fan of the super advanced medium size vessels than the klutzy artificial planets with a single big gun.
Then, manipulate things behind the scenes. Secretly support both the unlawful factions and the lawful factions to keep them relatively strong and very much locked in conflict, so that I always have job opportunities. This is another reason for having a not-excessively large vessel - it wouldn't be able to run the more covert operations.
Something along those lines.