Just count the "V's" if you're doing stockinette stitch or ribbing. Include the stitch on your needle, above the last V. For example, if you look on the Cast-On page, at the second picture from the top, which shows Double CO in ribbing, you can count 12 V's. The bottom V was done during the cast-on, because that cast-on creates an already knitted row, and then there were 11 more rows done after that (that are shown in the picture).
If you're working in garter stitch, you can count the "ridges." Every two rows creates one ridge. If you have six ridges on the front, and six on the back, you have done 12 rows. 6 on one side and 5 on the other side means you've worked 11 rows.
Happy Holidays and happy knitting!
KnittingHelp Queen Bee
"Don't ask yourself what the world needs. Ask yourself what makes you come alive and then go do that. Because what the world needs is people who have come alive." Howard Thurman