You have to practice, practice, practice. Shooting below 80 is something a good majority of golfers everywhere have never done, and probably will never do. I'm sure you've heard/seen the stats that the average golfer usually shoots around 92.

To break 80, you have to be able to manufacture a score. Sure a lot of people can break 80 if they are striking every shot pure that day, but that's not a reality in golf. You have to practice your game relentlessly from 150 yards and in with I think more emphasis on putting that anything else. If you hit more greens in regulation, you'll shoot lower scores, period.