One trick that has always helped me is that I orient the flats of the nipples so they are always vertical or parallel to the ground (until the very end). Most adjustments are done in quarter turn increments. That way if you are making the wheel rounder and are tightening 2 spokes coming from 2 flanges, it is easier to keep track that both nipples are turned the same amount (at least for me). In the same way when you are truing side to side and one nipple is loosened and the other tightened. Towards the end this pattern of a quarter turn adjustments and doing both sides the same amount changes - but you are not there yet so there is no need so explain about that now.

My tip for Wednesday morning is that I focus on rim roundness a lot more than side to side when bringing the wheel up to tension. I just try to keep the side to side grossly correct as i tighten all the spokes. While I am doing that I use my Campy wheel dishing tool to see if the rim is centered over the axle nuts. If not (and it is almost always not) I tighten all the spokes in the direction the rim needs to go. This allows me to tell if there are any trouble spokes either too loose or too tight. Sometimes if it is far out I loosen all the opposite side spokes for the double reason that I am not only moving the rim in the direction it needs to go but also trying to discover if there are any problem spokes. You never truly get a wheel round so it is always possible to keep tightening 2 (or 4) spokes from opposite flanges as they hit your truing stand letting you know they are the loosest spokes in the wheel at that moment. Rinse and repeat many times.

You are always going to have issues around the seam. I often take a file to knock off a tiny bit of the excess sticking out just a bit.