The first (and most important!) step to becoming a pro golfer is to
study, study, study. Even the most talented golfers benefit from
hiring a PGA professional coach. The PGA makes it easy for you to find
teachers in your area; just go to:
http://www.pga.com/improve/find-an-instructor/ and use their form for
finding teachers in your area. The LPGA (Ladies Pro Golf Association)
has a similar form: http://lpga.nemexinc.com/directory.cfm
See "All Types and Abilities," the PGA's advice on why a pro teacher
is the very best way to improve your game:
Even while you're learning, though, you should compete in tournaments.
Your teacher will guide you to tournaments suitable for your level of
expertise. You will almost certainly need to start with amateur
tournaments, and work your way up into pro tournaments.
This may sound too simple, but it is the recommended way to become a
golfing pro: Study with the best, start in small tournaments, and as
your abilities increase, graduate into professional competitions.
Finally, you may be interested in the book "Become a Professional
"how to" pro golf
PGA pro teacher
"golf tournament" qualifications