Cartridge: (of course)
Date Loaded:
Bullet: (manufacturer, style, weight, and lot number)
Powder: (manufacturer, "number", and lot number)
Case: (manufacturer, case length trimmed to)
COAL: (or measure to the ogive with a comparator)
Velocity: (use the average, I usually include standard deviation as well)

Test conditions: (sky, wind velocity and direction in relation to your target, temp, humidity, altitude).

I usually fire a group and record it. If it doesn't shoot well, I know something's off and I may want to do some troubleshooting before I duplicate that particular load again.