New to crochet? Keeping straight edges in crochet is easier than you think. It all depends on one little difference, let me show you my trick! This is a good tutorial on keeping edges straight. A lot of pictures to go along with the instructions.
tiny crochet pompoms on a chain edge - full instructions - clever and so cute! chain 3 dc in the chain (keeping the last on the needle), chain repeat the cluster stitch, join with slip stich, chain 3 and go on :-)