Buy a sonic cleaner and learn how to use it. Clean brass is accurate brass with stable internal volume over time. Adding some residue each shot is NOT consistency.
Buy Nosler, Norma or Lapua cases. Sellier & Bellot loaded ammo makes a good alternative, as you can immediately fireform the brass and trim to your standard length. Virgin brass and fireformed brass take a slightly different powder load for the same velocity.
Winchester, Federal and R-P brass will have a higher cull rate and shorter life, so Lapua and Norma and Nosler isn't that much more expensive. Old Winchester brass was very good. The new stuff isn't the same. The way to get Nosler brass is shoot the Trophy Grade ammo and it is immediately fireformed without that needed extra expensive and you can buy enough and just hunt with that a while, or go out varmint shooting. I got mine for less than the cost of brass and bullets if buying components separately. Nosler sometimes runs factory direct sales on ammo, but not during times like today. Nosler brass is mostly made by Norma.
Some rifles that have perfectly aligned bores and chambers can tolerate immense bullet jump, while others cannot. Know your rifle.
Buy a chronograph and learn how to use it. Keeps you safe when working with hot loads. Long range loads tend to be hot loads.
Case capacity is important. R-P vs. Norma brass changes the powder load about 0.5 grain in my rifle. Fill cases with water, weigh about 5 of them, empty and full. Subtract the difference and divide by number of cases weighed. If running compressed loads, variations in case capacity affect compression quite a bit. Loads where you have less than 90% fill will not matter as much.
I always factory crimp to add a standard amount of startup resistance. Also adds safety as it prevents bullet setback if dropped.
Forget temp sensitive powders if hunting in varied conditions. I learned this the hard way. Losing velocity on a cold day not only drops the impact point, it changes the timing and changes the bullet pattern, almost always for the worse unless your load was a bit too hot to begin with. I just use Hodgdon Extreme powders and got rid of the problem.
Buy a good case trimmer. Double important if you factory crimp, as it keeps the crimp length consistent as well.