Practice does NOT make perfect.
Practice makes PERMENANT. If you are interested in becoming an average shooter, go to the range and blast away once a month. If you are interested in becoming an accomplished shooter, take a good class (SD, target, skeet, whatever your goal) up front to save the hassle of un-learning bad habits later. Good technique can make an average shooter into a better shooter very fast. Once you've got the basics, it's just a matter of doing them faster and farther away.