Joining a new color to crochet has always been one of those techniques that freaks me out--you don't want to see my early granny squares. But joining with a crochet stitch in pattern clears up a lot of weirdness and confusion. Joining with a half double crochet (hdc) can add a whole new level of trickiness to things because of the yarnover required to make the stitch, but with a good grip and the flick of your crochet hook, you're all set.
As I mentioned last time, knowing how to join new yarn to a project with the same stitch as what you're working in comes in handy when you're switching to a new skein of yarn or when you're switching colors.
Sure, you could crochet all your dishcloths in just one color but what if you feel like being fancy? Yes, I know you can make perfectly nice dishcloths in just one color (I like to believe I can do it myself). But colorwork always seems impressive to me, whether in knitted or crochet projects. It just looks so interesting, and it's always so difficult for me do. I know I'll eventually get there, but it's slow-going and I'm trying to allow for a certain number of screw-ups when I'm trying to learn new techniques like mixing in different colors.
In the meantime, I feel pretty good about knowing how to at least get started when I add new new yarn.
And I like to think a good start counts for something, don't you?