But before this thread gets deleted, here's the best I can come up with right now. Just do practice problems. If you can't do the olympiad ones, starts with U Waterloo's Euclid past years, then move your way up to the olympiad. Literally practice problems is all you need to do. The more practice problems you do, the more little tricks you come up with, and as you come up with more little tricks, the breadth of problems you can solve intuitively right off the bat, or at least with increased ease, will slowly expand.