I know that SO Many people have made diaper cakes, but a few months back I took a stab at making one. I think it turned out pretty cute. Just in case you haven't seen how to make one, I'll post some pictures on the steps to making one.
I started with a charger plate from the Dollar Store.
Roll up the diapers and place a small rubber hair band around each one to hold it in place. It's easiest to do this all at once and then assemble them.
Place a large baby bottle with a rubber band around it in the center. Slip 6 diapers around the bottle inside the rubber band. Then place another rubber band around the set of 6 and slip 11 or 12 more diapers inside that rubber band. Do the same thing with 18 diapers around the outer edge.
This is the base of your cake.
Build the middle tier in the same manner as the first, with 6 diapers and then 11-12 diapers.
Now build the third tier.
It will require a small bottle to complete the top tier.
Place ribbon around the middle of the diapers to cover up the rubber bands.
I only tied a bow on the top tier, but you can do this on all three if you want.
Now, complete it with fun as well as practical things like stuffed animals, baby spoons, wash cloths, nail clippers and small toys.