For this you can use new or recycled flannel, a flour sack towel, or really any absorbent woven fabric or fleece (poly or natural fibers). Starting with more stretchy fabric is harder unless you have a walking foot or are very practiced already with sewing stretchy fabrics. You can also use any sewing machine needle for something like this.
Choose the pattern you want to use and cut an inner and outer fabric piece.
* If you were going to apply snaps or velcro to the front of the outer, you would cut a piece of fabric for reinforcement and apply them now.
Lay the pieces with their faces inward towards each other.
Clip or pin them together, faces in.
I use a fairly wide stitch for the initial sewing.
Lower your needle into the front edge about 2/3 across the body.
Sew forward a few stitches and then reverses your direction for a few stitches.
Continue sewing forwards again and proceed to sew around the outer edge of the body.
I use the edge of my sewing foot to keep my distance from the fabric edge consistent.
When you get to the opposite side of the front again, sew back and forth for a few stitches again.
Sewn around the outer edges:
This will be your turning hole.
** For many types of pocket diapers, you would sew all the way around and turn through your pocket opening.
Reach your hand inside and pull the wings through.
I reach my hand back inside to push all my edges out evenly.
Now to sew your elastic casings. I use a little bit shorter of a stitch length.
Make sure the edges are pressed cleanly, and lower your needle to the correct width for your elastic casings.
Begin sewing back and forth a few stitches and then the length of your casing channel.
Finish it off the same way.
Repeat for your other elastic casing channels.
Now select your elastic. I used 3/8" polyester braided with a bodkin. You can use any elastic for your practice diapers though, and a safety pin works great as well!
Feed your elastic into your casing channel.
I feed with the outer fabric up so I can guide the elastic OVER the inside turned fabric edge and against the outer edge. This proves helpful when sewing PUL diapers later on and to stop little things like twisted elastics and unevenly puckered edges.
Feed the elastic all the way to just past the end of the casing channel.
Shorten the stitch length a bit more.
Remove your bodkin or safety pin.
Stretch your elastic so that you can still pull the fabric all the way straight but with good tension. I pinned it here to show, but once you are practiced, you won't need to pin through your materials.
Sew back and forth to secure, and then trim your elastic to about 1/2" from the end of the casing.
Repeat on the other side and fold over to measure against the first side before securing to get even leg openings. Then sew in the back elastic. I don't tighten the back elastic as much as the legs.
Once the elastics are installed and the bodkin or safety pin is removed, we are ready to close up our turning hole. Fold the fabric edges evenly inward.
Clip or pin closed.
Close your hole while top-stitching.
Finish top-stitching around the front and the wings.
Your basic practice fitted diaper is complete.
Very useful with added absorbency like a trifolded prefold.
You can even sew in or snap-in a soaker after-the-fact.
Most flannel is not snappiable, but you can use pins or even sew on hook and loop (like velcro.) However, a flour sack towel or fleece usually IS snappiable.
Adjust the size/rise by just folding over the front.
My free pattern templates can be downloaded for print here: