I have a 3 ring notebook with pre printed pages (think it's from MTM) that I use to keep track of loads as I test them. It has room for powder, charge, primer, distance etc. After I shoot the loads, I record the group size on the data sheet and toss the target. (Well, OK, I keep the really good ones
Once I have a load I like, that info is recorded on the box the ammo is in using either the labels supplied by the bullet manufacturer or some from a roll that Midway sells. On the ammo box label, I list bullet, powder type and charge, primer, case, # of times the cases are loaded, # of times they're trimmed, and a lot number. The lot number is assigned by me (1, 2 etc) and those cases are kept together. If I lose a case while hunting, then that lot runs with 19 in it instead of 20.