Look at the end grain. If the annual rings run like a deck of cards stacked up top to bottom it is quarter sawn, which is good for figure. If the annual rings are like stripes straight up and down its plane sawn and will be quite strong but not showy. If the rings are diagonal it may be subject to warping.
Moisture content.
Thickness.
Width of plank at least 8”.
Weight and hardness, if it is seasoned or dried.