Several posts ago I noted loose stitches at the heel flap edges of my Thuja socks - I wasn't very happy about that. As I worked the heel of my first Blackberrylicious sock, I paid special attention, hoping to tug the stitches tight for a better result. I didn't need to worry. The pattern designer instructs that each row of the heel flap is started and ended with 2 knit stitches - creating a garter stitch selvedge, and the result is dramatically better.
A bit of internet research (thanks to JoLene Treace) show that there are a few different selvedge strategies - stockinette (knit RS, purl WS), reverse stockinette (purl RS, knit WS), garter stitch (knit RS and WS), or reverse garter stitch (purl RS and WS). Slipping the first stitch of each row is another strategy, but this could make the second stitch looser, so this isn't recommend unless a loose selvedge is wanted.
Thinking about and learning about selvedge edges will make me a better knitter. With careful thought and planning, I can improve the likelihood of satisfaction with my finished knitted goods. It's those little details that can really make a difference.