Tips for Stranded Colorwork
Swatching with the Long Float Method
To make a small swatch in the round, knit as instructed, and then slide the stitches to the other end of your needle. Continue knitting, leaving a long float of at least 6" between each side. Your edge stitches will be loose and sloppy, but the middle stitches will give you a good indication of your gauge!
Locking Floats
To lock floats, bring the resting color over the working color behind the work before working the next stitch. Knit. Return the resting color to the resting position. The color that you want to pop (typically the motif color, in this case Color A) should be kept in the LOWER position. For Right Handed knitters, this would typically be held in your left hand.
Colorwork Tips
Knitrino recommends knitting stranded colorwork with two hands. The strand of yarn that is carried lower than the other on the wrong side will create larger stitches and can appear more dominant on the right side of the fabric, so carry the float of the background color in the upper position on the wrong side, and the motif in the lower position. For most right handed knitters knitting with 2 hands, you'll carry the background color in your right hand and the motif color in your left hand.
The floats should lie flat without being taut when the stitches are well stretched out across the needle. Adjust the tension of the carried yarn at the end of each round, if necessary.
If a stitch is pulled too tight and appears too small on the right side, it can be fixed by making a duplicate stitch over top in the correct color.