I’ve written down this very simple how-to because when I was teaching myself how to knit using different colors in the round, I did a Google search and came up with so many different methods. And because I’m crazy and obsessive, I tried out several different methods (some quite complicated and frustrating) and ultimately, I found that it’s really very simple! So here goes:
The first thing you have get over is the idea that knitting intarsia in the round is actually not possible because you’ll end up completing a row of color, make your way around, and end up with the contrast yarn at the wrong end of the pattern. So, fundamentally, you have to knit intarsia back and forth. There are a number of different methods that tell you to go back and forth only on the pattern, then to make your way around, remembering that you’ve completed two rows of the pattern and only one round of the rest of your knitting… Then, you have to slip those stitches, blah blah blah. It’s really confusing. Going back and forth makes the process MUCH easier.
When you come to terms with the fact that you’re simply going to be working the entire thing back and forth instead of in the round, then the only thing you have to worry about is joining the rounds as you work so that you don’t end up with gaps at the beginning/end of the round.
So, let’s say that you’re making a PSP cozy… 😉 Work the first row of the pattern. When you reach the end of the pattern (in Color B), you’ll want to work a few stitches of Color A. Then, turn the work.
Now, you’ll be working the purl side. However, before beginning the next row (and going back from left to right in the pattern), bring your working yarn to the front and yarn over on the right needle from front to back, bringing the working yarn back to the front of your work. Resume working the row, remembering to purl all your stitches instead of knitting them! Once you reach the last stitch of that round, purl the last stitch and the yarn over together. This joins your previous round with the current one.
Next, turn your work again. This time, you’re back on the right side (the knit side) of your work. However, because this is the knit side, you will need to hold your working yarn in the back. Bring the working yarn from the back to the front and to the back again on the right needle. You’ve created another yarn over that you will use to join with the row that you will know be knitting by knitting the last stitch of this row and the yarn over that you’ve just made together.
Continue doing this until you can resume knitting in the round (once the pattern has ended and you’re back to one color).
Please feel free to ask questions (via comments). If need be, I can add some photos to help with the process!