Ironing is important to achieve a professional look. I have found that only the pillowcases which I've ironed while making them will fold squarely for storage.
I finished the first two pillowcases a couple days ago (click here to see them):
I have shown that turning the hem also forces the pillowcase seam to one side:
By steam pressing this seam to one side along its entire length, the final pressing is neater:
For the final pressing after assembly, I first turn the pillowcase right side out, and poke out the corners with my fingers. Then I lay the pillowcase on the ironing board with the hem edges matching and the seam to my right.
I start by pressing along the seam, carefully folding along the seam, and press towards the opposite side. I pull the pillowcase towards me and iron the next section, and so forth, until I get to the seam on the end opposite the hem. Starting from the right side, I pull on the seam so that it's folded along the seam, and press it, doing these both for about two inches at a time, until I get to the left side.
Here are the last four pillowcases:
I guess this means I can get back to sewing on my dress, huh?!? (Click here to see the dress project.)