Wheel alignments aren't just about setting the car up to the specs in the computer. Well, party it is. But, with everything else, you should REALLY understand what your doing before you start playing with someones car. You should understand the angles, what they do, how they effect how the car handles. You should know the theories, how to compensate for road crown, how to diagnose drive ability issues. All that comes with time and practice. At my job I did nothing but wheel alignments for almost 3 years. It's nerve racking, and at times frustrating. But to set up a car to custom specs or diagnose and fix, nothing can describe the feel of the car after wards when it's perfect. Or maybe I'm just a little too into my job
But before you bring your car to a shop to get an alignment done, have some knowledge. Do your homework. An experienced tech should already know the in's and out's of your car, where the adjustments are, so on and so forth.
Just be smart, it'll save you money in the long run.