Cut your cardstock 8 inches by 6 inches....Score the 6 inch side at 1-1/2 inches and 4-1/2 inches. Score the 8 inch side only up the the 1-1/2 inch and 4-1/2 inch scores at 1-1/2, 3 and 4-1/2 inches. Cut only up to the score lines at these same lines. Cut the top part that is above the 4-1/2 inch scores completely off as shown below.
Here it is in a planning stage so that you can see the edges.
Complete decorating the toenail polish holder.
Here's a link to an updated version with a VIDEO made in 2018: Beachy Nail Polish Holder