Align two granny squares with right sides facing or as desired
Match corners and stitch counts along each side
Use yarn needle and yarn tails for invisible join
Whip stitch through back loops only for a flat seam
Mattress stitch for a nearly invisible join
Slip stitch join with crochet hook for a raised seam
Single crochet join for a sturdy decorative seam
Join-as-you-go while crocheting the final round
Place squares side by side and work through matching stitches
Start at a corner and join corner spaces first
Keep tension even to avoid puckering
Weave in all ends after joining
Block squares before joining for even edges