1. The first thing you want to make sure is to check that a crib your have bought
(whether new or used) is not on a list for being a recalled crib. Another great idea is to purchase a crib that transitions into a bed as your infant will grow faster than you sometimes realize.
2. Make sure that you are following the manufacturers directions when putting the crib together, and that you do not end up with a bunch of left over parts when done. Remember you are putting together something that is to be a safe haven for your child not a desk. Check the slates when done to make sure that they are no more than 2 3/8 inches apart, and that the side rail that lowers has no less than two locking devices to hold it in place.
3. Make sure that if you bought the mattress separate that it is a tight fit within the crib and not loose and floating around. Not only do you want a tight fitting mattress you also want one that is firm as a soft mattress may play a role in Sudden Infant Death Syndrome. Make sure that the bedding you buy is also a tight fit to the mattress. You do not want a loose sheet that could suffocate your infant in the middle of the night.
These are just a few tips to help in trying to choose a good crib for infant, be sure to read more than just this and to educate yourself as much as possible on cribs. With things like suffocation and SIDS you want to make sure that you eliminate as many possible situations that may arise from your infants crib. Being the leading cause of injury, and death among nursery products become an expert on cribs. This will give you a good piece of mind at night when laying your infant down for bed time.