Use good brass - Norma, Lapua, Winchester. Stay away from Federal, unless you are loading it once (once fired that is) and throwing away because the primer pockets open up.
Use match primers. I use either Federal 210M or CCI BR2 (LR), and CCI BR4 (SR).
Trim brass to the shortest length of the batch.
Single stage press. Mine's a RockChucker.
Use decent dies. I'm using Bonanza BR dies.
As for powder, use what the rifle likes. I'm using RL15 for .308 (it hates Varget) and IMR4198 for .223.
Good luck on the journey.