How high you set it depends on the terrain that surrounds you. If it is all flat, then it is recommended you set it anywhere form 17 to 24 inches high. If the area is sloping, you will need to adjust accordingly. Tree higher than area you expect deer to be in = move camera down. Tree is lower than area you expect deer to be in = move camera up. Now, I am not familiar with all trail cameras, I can say that the Moultrie Game Spy cameras have a laser aiming switch.Switchit to "aim" and scoot back to where you expect the deer to be. stand in front of the camera and look on your colthes for that red dot. ( If you have a piece of black poster board or something like that it is easier ). It is also easier if you can wait until late evening ( sun going down - or at night even ) Anyway, find the red dot and see how high it is, and compare that to how high the deer there where you are stand. Then adjust accordingly.

One last thing, You don't want to set the camera too close to where you expect the deer to be standing, walking, or crossing. Most of the Game cameras have an effective flash range of about 30 feet. You want the flash to reach beyond the area where you expect them to be at, so I set mine with roughly 1/3 of the flash range behind them. so I would set it about 20 feet away. But that is just how I do it. I am sure you could get 100 different methods from 100 different people, you just have to find what works best for your situation. But you can use this as a starting point.

Good Hunting
God Bless