Knitting pieces together

I was wondering if anyone has some ideas on how to knit or sew pieces together. I’ve just started knitting a year ago and this is my first afghan- I decided on an easy square patch pattern, but I’m not sure how to bring them all together nicely! There are about 16 squares of three different colors. Any ideas I’d really, really appreciate!!!

http://knittinghelp.com/knitting/videos/bas-tech-more/mattress-stitch.mpg

This is my favorite joining technique. Works great for sweaters.

For blocks of an afghan, though, it might be better to join them end to end–picking up part of a stitch from each edge back and forth. This way they meet flat, if you know what I mean.

Found a picture! http://www.knitting.co.nz/site/page_affix/toaffix_learntoknit13/