What do i do once i have finished my screenplay?

Try to get into a good film school and try to produce it there. Once done, you have more power to shop it around. In the states, best film schools are USC, UCLA, and NYU. Unsolicited mcripts are unwelcome by most in the film business. It opens up a can of worms of them possibly being sued. Best is to move to an area where they are plenty who work in the film industry and start rubbing elbows and get to know the players.