Updated by Kathryn Vercillo  So, let’s begin by crocheting a few rows of single crochet in Color A. When you are ready to change colors (to Color B), you will almost complete the row that you’re working on with Color A. You will totally complete the row in Color B and use Color B to work the next row. To begin the process of changing colors, work as far as the last single crochet stitch in the row, but leave the last single crochet stitch unfinished. You might have to tug gently on the yarn end of Color A to keep the Color A loops from getting too big. This gets easier with practice. For now, just work on getting the motions down. If you don’t plan to use Color A again within the next few rows (or simply prefer not to carry the yarn up the sides) then it is time to cut Color A. Leave a long tail of yarn - at least six inches or so. You will have to weave this end in later. Alternatively, in some cases, you may be able to work overtop of the end. This is not as secure a method as weaving in the ends, particularly not if you crochet loosely or if you are working in a lacy stitch pattern. The main advantage is that it’s quicker than weaving in ends. Use this method for projects that won’t be laundered frequently - for example, doll clothes. This technique works best if there is not a lot of contrast between your colors. If you are going to be crocheting complete rows of one color and then switching to another color, congratulations, you now know everything that you need to know about changing colors in single crochet! You can use this information to help you learn how to change colors in other stitches as well. However, there is one more thing that you might wish to learn, which is how to change colors in the middle of the row. There are different techniques for doing so. One great option is to learn the basics ​of  tapestry crochet.