Step 1: Cut the Pillowcase
Start by cutting the bottom 10" or so off the bottom (closed end).
Step 2: Fold
Next, fold up the cut end twice so that the folded end lines up with the hemmed edge of the open side. If this is confusing, you can look at the diagram I included at the end. The reason I folded over twice rather than just folding up once was because it allowed me to skip hemming that edge as well as give the apron a little extra thickness.
Step 3: Sew
Now, sew along the two edges as well as two times in the middle; this will give you three pockets. Just measure your pillowcase to know where the seams should go; I had to measure in about 7" from each side.
Step 4: Attach Ribbon
For the ties, I used thick ribbon but this is also open to your own interpretation. I ran the ribbon lightly through a match to seal the ends and prevent fraying. Then I folded down the edge and sewed it to the front of the apron.
Step 5: Overview Diagram
That's it! I liked this project because it was SUPER short and easy. It also is open to lots of tweaks and personalization. Fabric appliques, extra pockets, contrasting edging, etc.
Here's the diagram on how I did it.