When you work Fair Isle with one hand, you knit and purl as you normally do, dropping and picking up the different yarns as you need them. To practice one-handed Fair Isle knitting, choose two colors of yarn: MC and CC (main color and contrast color). With the MC, cast on 21 stitches and use the charted design in Figure 1. You can repeat the two colors throughout, or you can reverse or change them after every 4 rows. It's worth trying out the chart both ways to see how a simple color sequence change can completely alter the effect of an easy two-color pattern.
On the knit side
Start your row with the MC and knit the number of stitches called for. (If you're following the chart in Figure 1, you'll knit 2 stitches in the MC.) When it's time to switch to the CC, drop the MC, insert your RH needle in the next stitch, and then wrap and finish the stitch with the CC. (You don't need to tie on the new yarn. You'll come back and weave in the end later.) Work the number of stitches your chart tells you to in the CC (5 stitches in Figure 1).
When your chart tells you to switch back to the MC, drop the CC. Spread out the stitches just worked in the CC, find the strand of MC, bring it over the strand of CC that's hanging down, and knit the next set of stitches in the MC (see Figure 2).
So far, so good. One more move and you're home free.
When the chart tells you to switch back to the CC, drop the MC. Spread out the stitches you just worked in the MC, find the strand of the CC, bring it under the strand of the MC left hanging, and then knit the next stitch in the CC (see Figure 3).
Here are a few tips to steer you toward successful Fair Isle knitting:
You may want to recite a mantra as you work, such as "green over, red under." You also may want to add "green 1, red 5" to your mantra if your pattern is a simple repeat — just to keep you on track.
Designating one yarn as an "over" yarn and one as an "under" will keep your yarns from becoming tangled. It also will give you a very tidy-looking wrong side.
When you've worked back to the first stitch you made in the second color, the loop will be big and sloppy because you didn't secure the loose end of the first color. Give a little tug on the end hanging down, and it will jump right into line.
On the purl side
Purl in the MC to the first color change, and drop the MC (don't forget to spread out the stitches!). Pick up the CC, bring it over the MC, and work the next set of stitches in the CC. When it's time to change colors again, bring the MC under the CC. Figure 4 shows this process in action.
If, at the first change from the MC to the CC, the strand of the CC is several stitches left of your position, be sure to allow some slack between the last stitch of the CC in the previous row and the first stitch of the CC in the new row. Spread out the just-worked stitches on the RH needle before starting the next color, and keep up an under/over rhythm to minimize tangles.