Everyone should develop a system which is comfortable for them. Since I'm older than dirt and can't remember anything, I do this:
Using M.S. Word, I produce a loading log for each set of cartridges I make. I number them consecutively starting with Load # 001.
I set up a table with a column for the variables I want to keep track of; i.e. kind of brass, powder, charge weight, seating depth, date of production, bullet type and weight, etc. Then I have a note section where I write how many I made and why I made this batch. For example, testing seating depth, testing charge weight, testing tuner settings, or whatever. If I did something out of the ordinary, such as full length size rather than neck size, then I note that too. I also note if the powder was individually weighed or if it was dispensed via an automatic powder drop.
Then I copy the important data and paste it to another page where I format it as a label which is sized to fit the top of my standardized ammo boxes (they hold 50 rounds of .223). I print a label for each batch, cut them out, and tape the labels to the top of the box so that I have a record of the pertinent information. When I pick up a box of ammo either from my storage shelf or our of my gear bag at the range, I know exactly what I have in hand.
If I'm doing something like testing seating depths where I might load ten rounds at five different lengths, I make note of that on a little card I tape to the inside of the box lid. It is divided into a grid of 5x10 matching the slots in the ammo box, much like a Whitman's Sampler box of candy. When I'm chambering those rounds, usually one at a time, I flip open the lid and pick out the appropriate round based on the chart inside the lid. That way I can tell which rounds are which and fire them at the correct target, which I also carefully keep track of while I'm shooting.
See part two since I'm limited to 2000 characters.