How to remove spoke twist
There are two things I generally do to help eliminate most of the twist. 


When tightening spokes, get in the habit of slightly overturning and then turning back. (i.e. If I want to tighten a spoke 1/2 turn, I'll do 3/4 and 1/4 back. ) 
At regular intervals once the wheel is "close", take the wheel out of the stand 
and place the wheel vertically on a soft surface like a piece of carpet or wood. 
Lean your full body weight on the on the top of the rim. Turn the wheel slightly and repeat until you've done at least one revolution of the wheel. This simulates the load the wheel will encounter during the first ride. You should hear the same kind of pings. It's important that whatever you put the wheel on is softer than the rim material, you don't want to put any dings or dents in the rim.


Neither of these techniques is perfect, most wheels I've built require a bit of initial tweaking after the first week or so. But they will get you much closer.