Take the time to look at a copy of the magazine. Often a magazine will reveal its audience in its slogan or mission statement. Communicate clearly the value of your information. You have precious fews seconds to convince me. Ask for an editorial calendar.
Many publications plan their editorial content months in advance.
When you request a sample copy or writer's guidelines, ask for an editorial calendar. Offer a few tips or an excerpt from your book as a sidebar for an article on a specific upcoming topic. When you zero in on a specific subject, you increase your chances of getting coverage, and you help out the editor, too. Send a cover or slick. I want to check yes or no for a review copy of the book.