What is the best way to bring up my GPA?
I would take some classes that interest you or seem a little easier to bring up your GPA.
Taking a lot of classes and getting a low score on some would lower your overall GPA average. So, I think taking the minimum units required will help retain a high average for you.
It's easier to get a 4.0 when you aren't taking a lot of extra classes, but it's also more expensive because it would take much longer.