Does working on one section of a wheel rim often/usually cause another
section to go out of true?
You should have adjusted the spokes on the opposite side of the wheel,
not just the ones on the opposite side of the rim.

Is it worthwhile to try to get rid of all the little wows in the rim?
How much free time do you have?

Is there a reasonable way for a newbie to judge correct spoke tension? I
It used to be done by the tone of the spokes. I prefer a $50 Park
tensiometer, and an Excel spreadsheet.
http://www.parktool.com/repair/howtos/TCC_version10.xls


have read a couple of articles by wheel experts, and it seems testing by
hand is almost an aquired art. Any tried and true simple methods
recommended?
Try this book, it's a good start.
http://www.amazon.com/Bicycle-Wheel-.../dp/0960723668