Ok, let's do this. We're swatching again. Cast on 20 stitches, all in color A (of your choice, but of appropriate weight for needle size.) Now, for the next row, purl.
**Now it starts to get fun. Working in stockinette throughout the project, you're going to pick up a second color (b), and knit 3 B, slip 1 A. When you slip the stitch, you transfer it from one needle to the other without knitting it, or turning it. K3B, Sl1A across. Turn your work. (You'll notice that yarn B is at one end of the needle, and yarn A is at the other. Don't worry. We'll go get it.)
Ok, time to purl. Slip the As and purl the Bs, all the way across. Make sure you don't twist the slipped stitches!
Now knit across in A, then purl your way back. **
The four rows above represent the whole pattern, which comes out very cute. For those of you asking, "where's the picture?", where's the fun in that? 80 stitches from now, you'll know how it looks, and you'll love it. And wasn't that ridiculously easy? I know. I used to be scared of them, too. Now I feel very silly.
You may have noticed there are no directions telling you where to hold your yarn. Usually your working yarn stays where it belongs - when knitting stitches, you just slip the slipped stitches without moving the working yarn to the front. (Which is probably what you did, anyway.) That means that when purling the working yarn, you won't move the working yarn to the back while slipping stitches, either. In some different slip stitch patterns you'll see directions reminding you to hold your working yarn to the back or to the front. This is important to notice, as you won't get the desired effect if you don't put the yarn where the pattern tells you.