Writing an article or book about something you know very well?
Seems like an odd question, and title.
A familiar topic would sure be a lot easier to write, you know what the readers read, and having it on those pages would strengthen your perception of expertise to the editor. (But if you are empire building and this article is part of the core of your empire, right now keep that to yourself. Editors flee if they feel they are being used.) If, for example, you know widget shipping and you want to write “How to Quickly and Inexpensively Ship Widgets,” bingo!
Don’t shy away from these kinds of articles—where you are well based and have experience—but there are things you must be aware of, like the pace.
1. If it’s a new editor (to you), sell yourself modestly. Only sell the key article you want to put in print. Write a super query letter—and don’t bug the editor if she responds a few days later than you expect.
2. Let this editor realize on her own that you will be a long-term benefit on her pages, by performance. Make the article hum; keep it the length suggested, and get it in on time.
3. After it is bought, send a new query with another article suggestion about a topic that also seems irresistible to the editor. Still, with humility and proof that you can convey the goods on paper.
4. If there is also an association of widget shippers, and it has a magazine or newsletter, follow the same modest path suggested above. This piece should be different than your article in (1).
5. Since the editors read the others’ publication, they will “discover” this new gem in their field: you!
6. See if you can get a seminar, speech, or workshop scheduled at the next association gathering using the topic of one of these articles.
7. Now is when you write the core book about your expertise, and extend your empire into the future around this topic with more articles, speeches, workshops, classes. (Consult too.) If you have a publication date for the book, mention that in the bio plug with the articles. If possible, have the books available by the time you do your major speaking.
8. The example above is for niche publishing, where you should also pre-test your book before writing it. But there aren’t many changes (other than pre-testing) if your topic is broad or general.
This blog mostly helps with the order of things, starting with articles. It also talks about gently selling yourself, with humility in querying.