Step 1: Gather your materials. Basic items you will need are:
-diapers (I highly recommend Pampers Swaddler size 1 or 2...they are all white, they are soft and even if the newborn is 8+lbs at birth, they'll still fit!)
-cardboard or cake board, tissue paper
-ribbon (fabric ribbon, not gift wrap ribbon)
-scissors, hot glue gun, tape/double stick tape
-any accessories that you want in the cake (in this instance a hooded towel, washcloths, a travel soap/lotion set, a small pkg of wipes)
Once it's all rolled up, wrap it with a rubber band. Again tight enough that the diaper doesn't unravel but not so tight that it leaves a huge indention.
Here is my bottom tier, for a 3 tier cake. I labeled it to show what I mean. There is one diaper in the middle labeled "center". Then 3 circles of diapers surround it.
Now stack your top tier.
Now if you have any washcloths, burp rags, onesies, etc that you are wanting to include, roll those up to approximate diaper size and substitute them in.
(I circled where the hidden skewers are..)
Tada! Your cake is now finished :)
Now if you want to wrap it up in tulle, you can do that now. You'll need about a 1.25yd of tulle (again, it's like $1/yd at Hobby Lobby) and you just place the cake in the center of the tulle yardage. Pull the tulle up and rubberband it just about the top tier. Cut the excess off, attach a ribbon to cover the rubberband and you're ready for gift giving. (I made this cake just before taking it to the shower, so I did not wrap this cake in tulle.)