Here are some important things to look for in your doelings. Width in the escutcheon (width between the rear legs). This shows the room for an udder.
Teat placement, size and shape. Look for teats that are hanging plum and of nice size.
Look for a smooth and level top line. Watch that rump that it is not sloping. Look for levelness in the chine (this is the area right behind the shoulder blades).
Look at the rear legs that they do not turn inward.