Candle them, especially looking for cracks or weaknesses in the shell but also anything unusual inside the egg. The larger the air sac the older the egg so go with smaller air sacs.
Select regular looking eggs. If you have to eliminate any, eliminate the ones with ridges or strange shells.
Pick average sized eggs for the breed. Don't set unusually small or large eggs. Remember to compare them to the others ofthat breed, not all the others.
Choose against the ones that are dirty, especially with chicken poo.
Anything I left out????
Odds are this criteria won't help you much as I suspect the breeders shipped good eggs to you. Most people try to do what is right.