This was the outfit I made for Addie to wear while we were at Disneyland for the Tupperware Jubilee.  I got TONS of compliments on it and asking where I bought it or even if I would make and sell some. (tempting!) 
 It was actually pretty easy.

For the skirt:
I got 1/4 of a yard of black, red, and yellow fabrics. (the red and yellow were with the tulle and were a little stiff but transparent and soft) 
If you are doing a larger size skirt you’ll want to get more fabric.  My baby is 6 months old so 1/4 of a yard is pleanty.

First you want to sew the edges of the red and yellow fabrics.  I did a zigzag because I knew the thread would show and thought a zigzag would look cute.  Then you want to sew the end together- so you will then have a large loop with one side zigzaged.  Do this for both the red and the yellow fabrics.

Next you want to do a gathering stich along the top of the red and yellow fabrics together (the only side not sewn at this point). Now they are sewn together and you can pull one of the threads to gather them both for your ruffled look.

Next you want to sew the gathered part to the black fabric (you want to have sewn the black fabric edges making a big loop first)  Make sure you sew it about 2″ from the top so you can turn it down to make the waist band. (you can see how the red and yellow fabrics frey easily)

Then turn down the top and turn the very edge under and sew making sure you have a large enough waistband to fit the width of your elastic.  Be sure to leave a gap to put your elastic in!
Then  thread your elastic through, sew some ribbon (optional) on the edge of the black layer, or turn it under and sew it so there’s no unfinished edges.  And you’re done!!  I made mine layered so that each layer would show by having each layer longer than the one above it.

For the Onsie:

I took the same ribbon used for the bottom of the skirt and cut a strip showing each part.  Then placed them on a onsie where I wanted them and outlined them with puffy paint to hold them in place.  Make sure you put a brown paper bag between the onsie in case the puffy paint bleeds through.

For the bow:
I used some matching ribbon and a resin and made the bow I learned how on this website.

All together-