First, you should have some type of idea of what to expect, based on the parents. You should know what you are investing in before the breeding.

Second, I look for fundamentals, like soundness of structure, movement/fluidity, attitude about toys/food. That "look" in their eye of being smart, or not and if you have the advantage of watching the litter as they develop, you can find out who is a problem solver and who is not.

Just some things I consider.