You don't have unlimited blaster ammo. Blasters will overheat if you sustain fire for an extended period of time. Knowing when, and how, to reload will help you stay alive and help you kill enemies. Both will help you net extra experience points.
Experiment with different blasters and figure out when it's best to pull off the trigger so that your gun doesn't overheat. For instance, DL-44 can only fire off a few shots before it needs to cool down. The DLT-19? It can shoot about 40 shots before you need to take your finger off the trigger. Memorize each one.
If your gun overheats, you can use a button press to cool it down a little bit faster. If you hit the button at the right time, your gun will instantly cool down.
Get the timing of the instant reload down and you'll be able to stay in the fight for much longer.