By the numbers!
Learning what your numbers are when you begin the process and watching the improvements is rewarding. The system is sophisticated but you quickly learn which numbers to watch. Your fitter selects different shafts, heads, weight and you swing. The process takes a few hours but is worth the work. Mitch did an excellent job, knows what to do to make the best fit possible for me and stayed within my budget.
If you want to advance your game, this is a great place to start.