Diligently following your baby crib assembly instructions is very important in order to ensure your baby's safety.
Make sure:
you read every step carefully
you don't skip any steps (do not assume some steps are not necessary)
all the screws and bolts are tightly fastened with the proper tools
all the crib pieces are in excellent condition (if not, call for replacement parts)
all the crib parts are included in the package
I also recommend that you call the manufacturer if you have any concerns or questions regarding your baby crib. If you choose to stick with a reliable crib manufacturer such as Graco, you will be pleased. with the customer service.
I remember making the mistake of assembling Samantha's Sorelle Crib in the living room, because there was more room to layout all the pieces. That was a mistake, since I had to lug it upstairs afterwards, and even scratched it in a few places, in the process.
A few things to keep in mind:
register your baby crib - so that you will be contacted incase the crib is recalled in the future.
choose a quality firm crib mattress to go along with the crib - I personally prefer organic crib mattresses
Once you finished assembling your baby's crib, make sure it doesn't wobble. Try shaking the crib to see if it does.
You should examine the crib on a weekly basis. It only takes a few seconds to check if:
for loose bolts
integrity of the slats
sharp edges
the mattress support
My last piece of advice: assemble the crib prior to your baby's arrival. This will give you time to check that everything is working properly, and it's for your baby to sleep on.