Are you doing garter stitch?? (knit every stitch of every row)
If so, you'll notice that your knitting, if you pull it apart slightly, has raised 'ridges' that look like two loops intertwined, and then between the ridges you have a lower row that looks more like V's. Each ridge is one row, and each "valley" (for lack of better wording!) is a row. So what I usually do it count only the ridges, and count by two's, because unless you stretch your knitting apart you don't totally see the "valley" rows.
Hope that helps.