I made this little video (its about 20 seconds long and has no sound) about two years ago and just located the file on my computer. So many people ask me how to join granny squares, this is an extra quick method using double crochet(UK)/ single crochet(USA).
Place two squares together with right sides or wrong sides facing depending on if you want the ridge on the inside or outside of your finished item.
If you want the ridge on the outside (place wrong sides/ back of squares together) or for the ridge on the inside (place right sides/ front of squares together). You can use the same colours as your granny squares or a contrast colour and go through both squares and make a double crochet(UK)/ single crochet(USA) into each stitch when you get to a space or corner make 2 double crochets(UK)/ single crochets(USA).
Join the squares into lengths first, than join the lengths together.
For granny square instructions with UK crochet terms goto http://www.nezumiworld.com/crochet_027.htm
For granny square instructions with USA crochet terms goto http://www.nezumiworld.com/crochet_028.htm
For granny square with a diagram using crochet symbols plus instruction on how to make granny square wire earrings goto http://www.nezumiworld.com/crochet_058.htm