Trophy connections has got the answer, hunt the in-coming trail!!!
Big bears usualy circle the bait just out of sight, if you can find where he is coming in, you just may get a crack at him.
Putting out less bait creates competition, but if someone else has a bait within a mile or so from you, they will usualy spend more time wherever they are eating better, so it does not always work. Heat also has alot to do with movement, if you have hot weather, they tend to be a little slower going. Bumber crops of beechnuts, berries and mountain ash will also cause problems, if they have a window to be able to feed on crops that die out, they will spend more time with the natural foods, because they can eat your bait anytime...especially at night!!!