What you need:
- graph paper
- pen or pencil
First, figure out what size you want your crochet pattern to be. My envelope purses are usually a width of 25 or 27 stitches and folded to a height of about 15 rows (so, excluding the closing flap, it's about 30 rows total). When I design my pattern, I draw a graph of the back of my clutch.
Second, design your pattern. Once you've graphed the size of your clutch, play around with the squares and figure out what pattern you want. Adding round shapes is hard, so it might require some erasing and altering. Sometimes I color in each square that is part of my design to help set it apart from the background.
Finally, start crocheting. Depending on how you made your pattern, you might need to crochet for a while before you have to pay attention to your graph. I always crochet the front half of my clutch first, and then continue with the back and the pattern.
Actually crocheting your pattern can be tricky. If your design is very intricate, you might have to switch colors a lot, and if you're not careful, it can look sloppy. Sometimes it helps to crochet over the color you're not using. This allows the string to be right where you need it when you switch colors again. I would recommend only using a couple colors at first, to help you get the hang of switching colors back and forth and find your groove.
I'd love to see what designs you come up with!