3 YARN TECHNIQUE
I saw this idea in a video called 'The art of knitting', in the chapter by Laura Bryant. It combines 3 different yarns, but drop each of them at the end of the row.
So starting first row with let's say green. Knit 1 row with green.
At the end of row 1 attach the next color- let's say blue.
Knit row 2 with the blue yarn (purl if you are doing stockinette sts)
At the end of row 2 attach the next yarn - say purple
Knit row 3 with purple
At the end of row 3 - the green is waiting ready to be knitted as row 4. So at the end of each row I drop the yarn I worked with and knit the next row with the yarn that is waiting for me right there.
How to attach a new yarn? leave a tail of 3 inches hanging. After knitting couple of rows take a crochet hook and weave that tail in through the little ridges on the purl side.
What to do with the yarn at the end of each row? let it hang loose until you need it again
What if I made a mistake and used the same yarn in the next row (instead of switching to the next yarn)? - it will just create a different pattern - that's ok - just go on knitting.
WHICH YARNS? I like choosing similar colors (blues and greens or browns etc.) and different textures. My favorite mix is a very soft yarn with sturdy variegated yarn and a special effect hairy or bulky yarn.
So - too many words, for something that is simple and thrilling!
When knitting with 2 colors, I love using Kaffe Fassette's idea of 'creating my own' ball of yarn. For example - when the design calls for blues and yellows, I will take all the blues I have, cut them in different length, and knot them in different order. This way I will create my own ball of blue yarns. I will do the same with the yellows. It is thrilling to watch the knitting unfold and see - what blue comes with which yellow and how do they look together.
DOUBLE YARN
Knitting with 2 yarns simultaneously can create fun effect too. I recommend using one simple yarn with a 'special effect' yarn (such as variegated, eyelash etc.).
All you do is pick the yarns and knit them together as if it was one yarn. In the photo below I used the same variegated yarn through the piece (autumn colors) and changed the plain yarn from dark brown to a lighter one.