Magic bullet is handy, but it doesn't have a very good luma curve, along with any of the Adobe Products. Apple Color is my favorite because it has a good one, and the grading process is done in "rooms."
First you should be color correcting before you do any grading. If you try and grade off of an consistent white/black points, the whole thing will be an inconsistent mess. What you need to do first is set your black and white points using a histogram. This should be the very first adjustment you make to any shot, because all other primary adjustments anchor off of the initial white/black points. Then you adjust your gamma as desired. Then, you want to set white and black balance; Final Cut has a handy tool that allows you to use a color picker and it does this for you.
Once you have everything chromatically neutral, then you can begin grading. There are many different approaches and theories to this, but one of my favorites is to use Monet's theory of complimentaries. That is, highlights should be complimentary to blacks. If you warm your mids/highlights, then make your blacks blue/magenta, you attain vivid contrasting colors while simultaneously maintaining equilibrium.
Above all, don't overdo it. Nothing looks worse than over-graded "videocam" footage. This is where scopes become invaluable.