How to use prior client list to market real estate services.

[Jason K.]

Ive been a contractor for 20 years and have been real successful using direct mail advertising to locate clients.  After 20 years I have a decent size list of people I have done business with.  I'm looking to jump ship from full time contracting in the next two years and head full on into real estate. Numerous people have mentioned that marketing to my list of clients is a great way to get my real estate sales career in motion.

Not sure how to begin this process.   What would you do with your list of 700 past clients?  How do I make the best use of this list and the relationships I have built.