This is what my DD's "screw" looks like...face and all. LOL!
I suggest that you work on the pitches that your DD is naturally inclined to throw. There are some typical paths but there no magic road map starting with this and working up to that. Keep having her try to spin various pitches until you find something that works and then stay after it. A pitcher with 2 great pitches is far and away better than one with 5 mediocre pitches.
RB DD started throwing the 2 seam this spring and it worked very well. She can consistently have it tail away from a RH batter but has a hard time getting it to tail in so she went to a screw ball release to get the ball to tail in on the batters hands much like what JAD likes. I've read the thread that Ken B (AKA Mr Bump) bumped recently and we're still working on getting seem orientation correct. Any thoughts on getting a 2 seam to tail in? Changing what side of the seams that the fingers are on?