Common to all pillowcases:
Finished size - approximately 21" x 32" with the opening at one of the short ends.
Fabric - cotton or a cotton linen blend. Does not need to be quilting cotton so check out the drapery fabrics for some interesting choices. Pre-washing is a personal choice. I usually wash after I have made the pillowcase to ensure there are no wonky edges.
Equipment - A serger makes a nice clean edge for the long seams, just shorten the stitch length for good results. A sewing machine is needed for hemming, french seaming (if desired) and adding decoratons.
Cut or rip your fabric approximately 2 yards long by 22 1/2" (which happens to be half the width of standard quilting cotton as it comes off the bolt). Fold the fabric, right sides together, to approximately 1 yard by 22 1/2". Serge the long sides together using a short stitch length. When you are serging remove the selvedge edge at the same time. Press the open edge to the wrong side with a 1/4" hem. Fold to the wrong side again about two inches to form a hem. Sew the hem from the wrong side. Turn right side out and press. Because you are working with two yards of fabric you can get two identical pillowcases from one length of fabric. Here is a picture of a simple pillowcase with a peak at the interior.
I got this fabric many months ago from J Caroline Creative and I think it is an older Amy Butler fabric design.
Cut or rip your fabirc (assuming quiting cotton again) approximately 3/4 of a yard long. Cut or rip another accent fabric about 1/3 of a yard long. Additional trim can be added of 3" of fabric or 45" of covered piping. Attached the trim and accent fabic to one raw adge of you fabric with a tight serger stitch. With right sides together, folded to approximately 22 1/2" by 27" plus accent fabric, serge the plain end of the fabric and the long side removing the selvadges. Fold the raw edge of the accent fabric to the wrong side about 1/4" then fold and press again to line up with the serged edge of the joining to the body of the fabric. I try to fold the 1/4" hem over the serged edge for a neater look. Sew the hem down, turn right side out and press. Here is a finshed example of this complex pillowcase with a look at the interior:
This pillowcase is made from several Moda Fabrics that were sold as a kit by Sun Flower Quilts here in Houston.
Use lace for the accent and trim fabrics. It saves the step of making a final hem or you can add another strip of fabric to have a clean finshed fabric, non-lace edge.
Finish off with a french seam. Essentially a french seam is constructed with the pillowcase serged with the wrong sides of the fabric together. The pillowcase is then turned wrong side out and the serged edge buried in a sewn seam.
Drag out your embroidery files and embroider the accent fabric before attaching it to the pillowcase.
Add a pocket to the backside of the pillowcase to keep the pillow from slipping out. Basically you will be making a simple pillowcase with an extra long back hem doubled over to make a little cover for the edge of a pillow. Extra fancy pillowcases you find in the stores usually have this feature.
Try the 'burrito' method of attaching the accent and trim. Essentially you pin the accent and trim to one end of the pillowcase fabric right sides together. Roll the body of the pillowcase fabric into a tightish roll then bring the right right side of the accent fabric over the body and re-pin. Serge/sew the accent/trim edge, pull out the body of the case, press, then top stitch the accent and trim into place.
These are very basic instructions but pillowcases are almost a no brainer once you have made a couple of them. They make great presents by themselves or as additions to the present of a quilt. One great place for inspiration is at an upscale bed linens' department. Check out the construction methods and adapt them for your own use. You will probably find that the even the fanciest pillowcases are made in one of the two ways I have shown above.