Q. How to I make sure other writers and editors don’t steal my ideas?
A. Some newer writers spend a disproportionate amount of time worrying about this.
It happens very rarely; most writers have enough ideas to keep them busy and don’t need yours. And the word would soon get out about editors who stole from writers submitting their work to them.
Occasionally you might receive a rejection to an article or query, then later notice a similar piece in the same publication. These coincidences do happen, but the publication has probably had that piece in the works long before you sent in your idea.
Few ideas are truly original (and ideas can’t be copyrighted). And if another writer ‘steals’ your idea, the end result will probably hardly resemble what you had in mind.
You’ll get more by sharing your ideas with other writers, then by hoarding them. By talking about current projects, there's a good chance others will offer leads, contacts and other information that will support your efforts rather than threaten them.
Read an issue or two of your favourite magazine, and brainstorm three to five articles based on the topics included in the issues you've just reviewed, but with a different focus/take on each of the various subjects.
You'll find even more writing exercises in my book 101 - and more - Writing Exercises to get You Started & Keep You Going. Check it out here.