Check out this excellent article (by Guest Star Derami of AllSux.com) over at One Man's Blog:

White Hat Digging: 3 Myths, Tips and Tricks for Understanding and Submitting to Digg.com

Especially helpful is his "Tricks of the Trade" section.

BTW, this is a great blog. I became addicted after just one visit. I even love John's tagline:

"Specialization is for Insects."

It flies (no pun intended) in the face of conventional wisdom and "stay on topic!" advice.