I saw this interesting article from Frank Chimero, whose art I am not familiar with. As such, I can’t tell you whether the efficacy of the advice is proven in his work. In fact, he seems to hedge his own bets with the title of the article “10 Principles That May Make Your Work Better or May Make It Worse.” Most of the advice sounds good from my experience, though.
I do take exception from the idea to sketch on crap paper. I hate crap paper. Not all cheap paper is equally good, but “Sketch Pads” that you can buy at an art store are atrocities. As though it was custom designed to make sure nothing worthwhile could ever be produced on the sketch pad. Typing paper is better. This is a source of some bitterness for me. Let’s move on.
Otherwise, I’d say the advice is all very good. I found Number 2, “Consistent voice is more important than consistent style,” particularly useful, as I sometimes feel reticent to try certain things for having too much awareness that it was outside my usual oeuvres.
Anyways, hope it helps.