The only things I would add to this:
1. Get a tensiometer. It is debatable whether pinging spokes and going by "feel" are really accurate enough; it might be ok for an experienced mechanic but for a newbie you should learn to use a tensiometer. For more info:
http://en.wikipedia.org/wiki/Just-noticeable_difference
2. Less is more. The amount of turn of the spoke wrench is probably less than you think. I spent a lot of time initially learning to true, turning the nipples far too much -- whole and half turns -- when really 1/4 and 1/8 were what was required. I wasted a lot of time and pulled out a lot of hair pulling the rim back and forth with a too-heavy-hand.
3. Get a tensiometer.
4. Worry about spoke wind-up. Especially when you're getting the spokes up into the higher tensions they need, wind-up becomes more of a factor and something you need to be concerned about. Spend some time putting stickers, pieces of tape, paper clips, whatever on the spokes when you turn the nipples to illustrate to yourself how much wind-up occurs. It is surprising, and it also teaches you how much relief (turning the wrench back) is required. Eg. Sometimes if a 1/8 turn is needed, you have about a 1/2 turn of just wind up before the nipple actually moves up the spoke threads. Then you have to turn back 1/2 to relieve that wind-up. So you tighten 5/8 of a turn and relieve 4/8 turn.
After you have some more experience, you'll find that when you're making final fine-tuning adjustments, you
may not need to loosen the opposite spokes. This is after you've gotten the wheel
mostly true, and you've gotten all of the spokes within 1-2 points of each other on the tensiometer, and you're making the final very small adjustments of like 1/16 turns, yes, in that case you can probably skip loosening opposite spokes.