While trying to work on a sweater with a lace pattern, I discovered that while I understood what "yarn forward" meant, I really didn't know exactly how to execute the knit stitch afterward so that it resulted in a stitch increase. I looked around the net and through my books until I found a good description in Debbie Bliss' How to Knit. Since I had both digital camera and a project handy, I decided that I could take pictures of the for others to use. Warning: I knit Continental, so these photos will show the yarn being held in left hand. Enjoy!

Step 1: The Starting Position

This is the way everything looks before the stitch. The yarn is in the position it should be after completion of a knit stitch. In my right hand needle, my thumb is obscuring one of the 4 stitches present on that needle.

Step 2: The Yarn Forward 

This is the way everything looks after you bring the yarn forward through the needles. Essentially, you are holding the yarn as if you were going to do a purl stitch.

Step 3: Starting the Knit Stitch

Insert the right needle into the first stitch on the left needle as if to knit.

Step 4: The Yarn Over

Now, bring the yarn over the top of the right-hand needle and behind.

Step 5: Wrap the Yarn to Knit

Bring the yarn under the right hand needle and over the top of the needle as if to knit.

Step 6: Knit the Stitch

Now bring the stitch through the stich on the left hand needle and remove the stich on the left hand needle (just as if finishing a regular knit stitch).

Step 7: Admire Your New Stitches

That completes the yarn forward, knit operation. There are now 6 stitches on the right-hand needle -- the 4 that were there originally, and the 2 new ones created by the yf, k operation.