A Blaster has a...steep learning curve. I hesitate to call it steep because it's a short trip to the floor. You will die. A lot. You have to fight dirty. The only rules of engagement are kill or be killed. Several tactics I've learned over they years are:
Enemy have nasty abilities? Hit them first, before they hit you. Don't forget to use any sleeps, holds, stuns, etc of your own to control the fight.
Hit them from out of reach. Hover blasting is a time honored tradition.
Run away and hit them as they catch up. Otherwise known as repositioning. Too many mobs? Aggro them and run away. Make them come to you. It'll stagger them out and leave them easier to deal with. Make sure you are running away from enemies and not into more of them.
Just run away. There is no shame in coming back more prepared.
And as has been mentioned, load up on inspirations. Don't hoard them, pop them like candy.