Truing wheels can be relaxing if you have a relaxed attitude towards it. It can either be art or science. You can literally do it by feel or by measurement.
Either way with a crusty old wheel I would start by putting a drop of light and/or penetrating oil on each nipple. I also like to put a piece of tape on one spoke so as I spin the wheel I can keep track of where I started.
Nothing wrong with doing it be feel. Literally feel every spoke and tighten any that feel loose. Then just spin the wheel and find spots out of true and tighten spokes to correct. YouTube always helps.
I tend to get a little more scientific and measure everything, but either way works.
Looking at your wheels and they look homemade. The spoke pattern doesn’t appear to align properly with the valve stem. It’s not a structural problem, but leads me to believe they were not professionally built. I wouldn’t worry about it, other than validating that they need to be trued.
I marked in red where the valve should be. Or maybe it is just the angle of the picture?
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