Like Pat said. The bark will usually tell you about what to expect the grain of the wood underneath will do, including twist. I try to find the straightest Osage tree I can, with the straightest bark, and as few limbs as I can. Even with that I end up with plenty of mildly snakey staves, staves that develop some mild twist, and most have their share of hidden knots to work around.
Like Burnsie said, the hard ones to find are the straight, clean ones.