All of the above is good info. A brake is pretty much a must have for spotting your own hits, especially with heavier recoiling guns. Best advice for serious hunting though is to have a spotter sitting behind you.
Following the trace can be a double edge sword however. Seeing the hit is the important thing, the trace will clue you in as to where it will take place, but don't get locked in on that, you need to be watching for both, BUT, especially the hit.
Wind can dissipate the trace also, especially at longer distances, and at extreme distances you wont be following it all the way to the target, as you will usually lose it at the apex of the trajectory.
Another thing trace watchers are famous for is telling the shooter his shots are going high.
You need to turn around and (insist) on knowing if he saw the actual hit.