I slip the first stitch of every row to make neat, tight edges.
For counting purls, use the bumps--there should be two very close rows of half-moons (at least that's how I see them!), and they alternate: one curved side down, one up, one down, one up, etc. That's ONE row of purl stitches. If you're counting purl rows in stockinette, count those half-moon rows. The form a sort of stripe, really, and are easy to see unless you're using fingering-weight yarn.