I've always been interested in the self-publishing thing and it's getting easier and more accepted all the time. I think "how-to" books work best for this as they can be smaller and still be marketable.
With the Internet, it's become even easier and more popular. My last two book purchases were both "self-published" ... on rabbit color genetics. One book can be purchased in PDF format to be downloaded, or on DVD ... or as a "book" ... which is printed by the author, one side page printing, in a 3-ring binder. The other book was published originally by a university press (I believe) but I recently found an updated version ... at the rabbit show, at a vendor's booth ... and the revised book has been published in a spiral bound version, which is available at places like Office Depot or can be done at home with the right equipment.
I also bought a self-published book on eBay several years ago on how to tell a horse's age ... again, I believe it was self-published, with a heavier cardstock cover with a printing setup that gives you a standard 8 1/2 x 11 page when folded once in the center. Put together with heavy staples and one of the "long-jawed" staplers made for this. A lot of people doing catalogs do this as well.
I suspect a good blend of on-line availability/ eBay and website sales of a hard-copy version would work very well.
One of the things I've thought about a bit recently, which would lend itself well to a blog set-up, is doing a series of "How to Draw" lessons ... basics first, one lesson a week ... then a series of specific subjects. The initial purchase could include the 3-ring binder and the first lesson ... could even include a basic "materials kit". Then they could buy each lesson as it came out or the complete series, all at once.
I can also see this working for a number of other "how to" things. Possibly a series of "how to" homestead type things ... again, basics ... canning, freezing, sourdough, etc., how to butcher a chicken ... rabbit ... hog ... wild game with receipes ...
This way, with a ring binder and the first "chapters" the buyer would have a place to put all of the information in one place and perhaps more incentive to buy more "chapters". A blog could announce each chapter as it was available, with some information ... expanded version (with illustrations, photos, etc.) available for purchase.
