Definitely watch the bark. The bark will show you how the grain of the wood inside runs. I the bark twist, the would twists, if the bark is snakes,so will the wood be.
I look for the straightest tree, with the straightest cleanest trunk and bark I can find. In spite of that you will usually find enough hidden surprise inside anyway. Pin knots, broken off twigs that got grown over, etc.
the chooses you are at the beginning, the betterff you will be in the end. Crooked,twisted, so-so Osage is easy to come by but harder to work with. Premium Osage is harder to find, but great to work with in the end.