1. Ensuring case lengths are within spec.
2. Checking for donuts (243, 270 and others)
3. For hunting ammo ensure that you COL is such that it fits the magazine and enters the chamber without obstruction.
4. Keep ammunition out of direct sunlight - I carry my hunting ammo in a shirt pocket (the extras that dont fit in the mag)
5. Don't leave propellant in the hopper when reloading. In dry climate moisture is lost and the density lowers. If you now load per weight as is normal, the charge will be more volatile and either you lose accuracy or you can get a spike in pressure that could be dangerous.
6. Use one make of cases for rifle reloading as case volumes can differ between makes.
7. Make sure the primers are seated below the level of the base of the case.
8. The only safe load is a starting load.
9. Consult different manuals, the internet and seasoned reloaders to ensure safe charges.
10. Pressure is a fickle thing. Rather err on the pessimistic side. Gaining 100fps , but shooting at max pressure may just wreck you cases.
11. Excessive barrel wear is directly related to too high pressures.
12. Inaccuracy is solved by elimination and can be an expensive exercise. Ensure that screws and bolts are torqued to specification and this solves many of those problems.