Lots of good advice offered here. I'll add my 2 cents.
1. Never, I mean never reload when you are in a hurry and have to rush things. This is formula for disaster.
2. Develop "fail safe" processes in your reloading procedures. For example, check all cases for powder before seating bullets, never have more than one can of powder on the bench top when reloading, double check, powder, charge, bullet before you start, i.e., do I have the correct components on the table and do I have the correct powder charge set.
3. At the range, make sure you have the correct ammo for the rifle you are going to shoot. Rarely do I shoot more one than one rifle at a range session but when I do, I only have the appropriate reloads out on the bench for the rifle I am shooting. The others are in the range box in their closed cartridge holder boxes.
4. If you encounter any unusual bolt lift, hard extraction, sound, recoil, or no impact on target, STOP, investigate. Never "test" the rifle / load by firing it until you determined the root cause of the unusual condition.
The bottom line is to be totally focused when reloading and at the range.