Doug-
I have been fortunate to get started doing this early, 31 years ago, I stopped counting at 1,200 wheels.
Here are some thoughts on building traditional crossed wheels, 3X or 4X., lets say.
Never assume a new rim is without fault, round or flat, test, don't guess.
A problem rim does not stop the process per se, but might limit its use, for show only...or for the front or both. Choose a rim label reading direction and stick with it. Check all new spokes to be used are the same length, double check if reusing spokes, yes, I have done that, recently retired a wheel that was made from donated Robergel spokes and a unwanted used Super Champ rim, built in 1973, thousands of miles. It can be done.
Be sure to make drive side rear wheel spokes shorter, saves time dishing and keeps spoke projection through nipple at bay, (faster = better here). Most of the spoke calculators with good measurement input data will guide you this way.
Take notes, rim model, spoke count, cross, hub combos for future reference.
Don't be afraid of oil, long ago old mechanics wives tale of oil on spokes will cause wheel to loosen up.... No, just the wheel was built too loose.
Drive side spoke pull direction is often a cause for much debate, I have a preference, drive side pull spoke with head out, but have built many either way with no noticeable change in performance. With and without opp. flange being a lacing mirror image.
Be sure to adjust in pairs as often as possible, sometimes 1/2 turn to two spokes on one side and one on the middle opposing works well.
Keep it round from early on!
Never cross the valve hole, (first lesson told to me, long ago)
Gots to be careful with those ol' Super Champion rims, the joint will often be off, and can adjust in the building process, I do not fix things with a file until near the end.
"Stressing" wheels to seat the nipple/spoke under torsional stress is good, I do it with radial pressure, not lateral.
I like DT spokes since first used them in 1975, but in the not too distant past the bend depth at the head changed, they then went back to the old, almost, so check them with a hub, if "loose" get fresh stock.
There's more, I guess I should go back to toil now, I am sure others have opinions.
John Jorgensen
Palos Verdes Ca