Groups of people willing to buy nonfiction books include hobbyists. At any given time, these people look for ways to spend their money on their hobbies. Their passion is your financial gain.
What avid hobbyists want and desire will always make great book material. Note: I did not say what hobbyists need. You may have certain opinions on what certain people should need or should read. But those are not necessarily good topics for immediate book profits. Those topics may be areas for you to dabble in at your leisure. However, if you want to make money at this, find what niche groups want, and hit those groups with your book.
Find hobbyists and niche groups by searching the web for "popular hobbies," "enthusiasts," or "what America is buying." Or, you can search for forums and discussion groups for hobbyists. In the forums, people talk with each other to share ideas. They exchange testimonials for equipment, upcoming events, and books.
One popular site where hobbyists hangout online is Yahoo!. Check it out. Go to Yahoo.com. Click "groups." On the group's page, you'll see a list of categories such as Business & Finance, Religion, etc. Click on "Games."
On the Games screen, Yahoo! lists game subcategories followed by numbers. The numbers indicate how many discussion forums are available for that subcategory. These numbers reveal a lot. Notice how "role playing games," and "video & computer games" have factors of ten, or in some cases, factors of 100 more forums than other subcategories. "Wargaming" and "paintball" don’t even come close, although those categories are much more discussion-laden than "horseshoe pitching."
For fun, one day I continued selecting subcategories until I arrived at a list of over a thousand (yes a thousand) discussion groups on Yahoo! having to do with vampire role-playing.
Here's how I got there: Games -- Role Playing Game's -- Live Action -- World of Darkness -- Vampire: The Masquerade.
Some forums are open to new members, and you can join to read what everyone's discussing. Once in the forum, you can review discussion threads from today, yesterday, or a year ago. Don't go back too far if you want to find the hottest possible book topics. You can participate in discussions if you like. FYI, do not drop into a discussion group just to market a book; hobbyists consider this spam and will drop you from the group.
When you read and/or participate, you'll find what this group is buying. Skim the discussions to find what questions they are asking each other about products or traveling or information. What they are interested in buying is vital because passionate consumers love to research before they buy. This is an immediate book market. Create a book on how to select the best this or that on the market, related to the current wants of the enthusiasts.
Enthusiasts come in all shapes and sizes. Think brides-to-be, golfers, whitewater rafters, people who collect vintage baseball cards, wine connoisseurs, gardeners, frequent vacationers, video gamers, and parents who put their children into private tutoring, ballet, and violin lessons before age 3.
Some hobbies continually attract enthusiasts, like playing golf, watching football, restoring old cars, and listening to music. These are classics. Some hobbies seem to come and go in waves, such as Red Hat Societies participation, snow boarding, or line dancing. Pick either a classic hobby or a fluctuating hobby in its peak season for your best odds.
A big market on the Internet is the 20-30 set. Here's what they are doing right now, according to one survey. They're snowboarding, wakeboarding, traveling, camping, listening to music, taking photographs. They're drinking gourmet coffee, rock climbing, playing guitar, camping, dancing, looking for online love, shopping for computers and other electronics, attending sports events, studying the Bible, exercising, trying to find jobs, and watching movies. Any one of these subjects make a great book with a buying market.