Whether I'm making my own bed or a clients bed, I don't like to shake out folded pillow cases to see what size they are and when they are the wrong size I need to fold them again. I prefer to glance at the pillow cases and know exactly which ones are what length. I've found a very easy system that works well for me.
Here are the steps with photos to show you what I mean.
Step 1 - Take a pillow case and lay it flat. (See below.)
Step 2 - Fold it in half. (See below.)
Step 3 - Fold it in half a 2nd time. (See below.)
Step 4 - Now fold it in about 3 inches (give or take). (See below.)
Step 5 - Fold it a second time. (See below.)
Step 6 - Fold it in one more time from the right side and once from the left side. (See below.)
Step 7 - Fold them together. (See below.)
See how the length of the pillow cases differ? I'm going to state the obvious, the long one is the long pillow case and shorter pillow case is the shorter pillow case. At a glance you can grab the correct one without extra work or trying to figure it out by the weight of each (which may fail if your arms are tired).
Folding in on both sides at the end will give it a bit more stability especially if you're standing them on end to store then in a standing file like manner.
Here's a different photo of fabric stored in a standing file like manner. It's easy to see the colors and pull the one out that is needed.
At home it's easier for me to get distracted. I need simple systems that guard my short attention span while doing chores, plus it makes my chores take less time. I'm so about saving time with simple systems that are sustainable when life gets crazy busy.