I tend to take an active role in the promotion of my articles, through a variety of channels, and I recommend others do so as well.

High-Quality Content + Good, Ethical Promotion + Proven Monetization strategies = $x,xxx per month.

I describe in detail the steps I take in my upcoming book on technical blogging. (Shameless plug: http://technicalblogging.com)

When I'm too busy to promote an article myself, my regular readers will usually do it for me organically. They are generally not as thorough as me, but they get the job done. :)

Your book sounds really interesting, thanks for the plug. Any other material you have that you can point us to?

Not at the moment, but I'm considering the possibility of turning http://technicalblogging.com into a blog on the subject. If I go for it, I'll announce it on the newsletter.

Right now I'm entirely focused on putting the best of my advice into the book.