It's not a bad technique for some applications... for me I only use it for bringing up the detail of areas of hair, fur, chain mail, engraving and of course groundwork, as mentioned above.
The technique has been described well... for colour, I start with a middle base, then drybrush with a couple of progressions of highlight tones, then use washes in the shadow colour... sometimes alternating between DB and wash. You can drybrush heavier on the higher areas of the part and wash deeper in the folds.
The deeper the detail of the sculpt, the better this technique works.
Happy brushing
Colin