You can take a square of flannel, hem it, then crochet a double-crochet shell pattern around it to make the simplest receiving blanket to welcome a newborn. You can also use this technique to add a handmade touch to a purchased receiving blanket.
Insert crochet hook through the flannel hem and pull a loop of cotton thread through from back to front.
Keep the loop on the crochet hook and insert the crochet hook from front to back again about 1/4-inch from last insert location.
Pull a loop of thread through the blanket hem and then through the first crocheted loop. You now have one loop on the hook again.
Insert crochet hook through blanket hem again 1/4-inch from the last stitch. Pull thread through the blanket and through the loop on the hook. Continue in this manner around the blanket hem until you have arrived back at the first stitch on the blanket.
Slip stitch through your first stitch on the blanket and through the stitch on the crochet hook. This is your first round of crocheting on the baby blanket.
Chain 3 to begin a double crochet shell pattern. Double crochet 4 stitches in the first stitch on the blanket. Skip the next stitch. Single crochet in the next stitch. Skip the next stitch and double crochet 5 stitches in the next stitch. Continue until you have your pattern completed all the way around the blanket.
Slip stitch into your first pattern stitch. Tie crocheting off and cut thread. Weave ends in.
These instructions are for a double-crochet shell pattern, but after your first row is crocheted on the blanket, you can finish with any crochet pattern you choose. Check that ends are securely tied and woven into the edging. The size 0 crochet hook easily pierces the flannel and does not require additional piercing. If you are using a larger crochet hook, you may wish to punch a hole in the fabric with a medium to large sewing needle as you work your way around the blanket edge.
Check blanket after laundering to make sure there are no loose edges for baby to become entangled in.