The tutorial at Sheldon Brown's website is a good start. I've built about 8 wheels, so I'm far from being a seasoned expert, but can share a bit of advice. Mainly, if a wheel is seriously out of true, or has noticeable flat spots and wobbles, it might be beyond what a beginner can work with. If it's an imperfect wheel that's been on a bike and is otherwise worth keeping, then probably the most important thing is bringing it up to a good tension, and then worry about tiny departures from perfect truth, and maybe a mm of wobble is rideable. Tires aren't more true than that.

Also, "the good is the enemy of the good enough."