When those guidelines and sample copies are in hand, you’re ready to start the hard work of marketing research. Read the guidelines carefully and use two highlighter--one color to highlight any passages that indicate this is a good market for your writing—and the second color to indicate that it’s not. Then read the sample copy or copies (the more copies you can review, the better) cover to cover. Make notes on any insights that come from that reading, such things as: likes first-person articles, has a folksy-friendly tone, uses lots of personal experience anecdotes—anything that will help you fit in if you decide to write for them.
For those that look like good prospects, go a step further and do a closer analysis of what elements the article includes. In the margin next to each paragraph identify the contents: anecdote, case study, statistics, personal experience, narration, quote from an authority, etc. What you are looking for is an indication of how much outside input is expected for a piece for this publication. Generally speaking, the higher the payment, the more research you must do and the more evidence you have to bring in to indicate this is more than just your idea.
As you go through your stack of guidelines and copies, you will be eliminating those you don’t fit in with and adding those you like to your growing list of publications that match your selected topics or types of writing.