I undertook my first "real" attempt at truing over the past few days, and it's definitely an exercise in patience. Although, once you start getting the hang of it there's a certain zen to it all...
I got my bike about 1-1/2 months ago from a fairly small shop, and unfortunately the wheels weren't trued up very well (mostly from settling in after the first couple of rides). Rather than take it back there and leave it with them for a few days until they got to it (it took them about 2 weeks to build up the bike after getting it in--small shop in spring=busy), I decided to do a basic lateral true myself using the brakes as guides. I'd done this a few times many years ago, so it wasn't much of a problem and only took about 15 minutes. That did the job, but I knew that the wheel wasn't really taken care of...
Anyways, last week I decided to order the Spin Doctor truing stand from Performance since it was on sale. It finally showed up on Wednesday, and I got started. I put the wheel in and started slowly spinning it and wrenching away here and there until things looked good. And they were pretty decent. I flipped it over to check the dishing and popped up the vertical true guide and checked that. Again, all in all, pretty good. Then I started plucking the spokes to check the tension, and they were all over the place. I knew the wheel was probably okay to ride for a while, but I figured I may as well keep at it and try to get all aspects more or less correct.
By this point I realized it was probably better to fully detension the wheel and start over since it likely had all sorts of cross-forces pulling every which way on it. I loosened all the nipples up pretty far, oiled them, and then finger-tightened all of them to get a decent baseline. From there, it was a matter of slowly bringing it up to tension (a few spins around the wheel with 1/2 turns on the nipples), then it was a matter of bringing it mostly into true, flipping, checking the dish, true, true, true, flip, vertical true, check spoke tension, true some more, etc etc etc. It took about 1-1/2 hours, but now, all aspects of my wheel are in good shape. It's round, it's centered, and it has (nearly) even tension all around.
The trick is a whole lot of patience, and dealing with the spokes in groups of 5 (1/8 turn loosen on the middle on, 1/16 tighten on the two adjacents, 1/16 or less loosen on the outside ones). Unfortunately, most of the guides out there say all that can be said on the subject--it's mostly a matter of doing it hands-on and being prepared to sigh, take a break, and then tackle a bit more a little later.
I think I'll save the rear wheel for next weekend.
Oh, and yes, get a real spoke wrench. The little crappy ones will chew right through your nipples. And read through the Park Tools page on truing
--the diagram there on "area of influence" helps explain the "groups of five" thing pretty well. Oh, and don't forget to destress the spokes every few minutes (give them a good squeeze or shove a wrench handle or crank arm in like Sheldon suggests). Good luck and let us know how you do!