There are probably many different routes to getting started as a writer. I know many writers and each one could tell you a different story.
Here's one approach you could try. You mention that you are a professional and have information to share - that is hugely valuable. So I'd suggest you start making some lists:
1. topics you'd like to write about
2. potential audiences (ie. seniors, new parents, women, men, snowboarders, owners of small businesses, etc.) Just list all the groups who might be interested in one or more of the topics that you want to write about.
3. publications that those audiences read
Pick one or two to start with. Let's say - just making something up - that you are a police officer and you have a lot of information on how to make your home safer. And you think seniors would be interested. But you don't know what seniors read.
So - you head down to the library or one of the big bookstores and grab a bunch of magazines aimed at seniors. What you want to do is analyze what the editors are looking for in articles. Some magazines publish mostly profiles - articles that tell about a specific person. Some do a lot of "how-to" articles. Some like first-person stories. You'll also want to look at things like article length, and how many experts are quoted in a typical article.
From there, you can create a proposal to send to the editor (called a "query" or "pitch.") There are whole books on how to write these, but basically you want to tell the editor what you want to write and why you should be the one to write it.
Let's say, for example, you find a magazine for seniors that has a lot of how-to articles of a practical nature, and you think they might be interested in something on making your home safer. The articles are fairly short, though, so you will need to narrow the topic. Let's say you decide to focus on inexpensive tips to make the outside of your home safer. (I am just making this up...) And you notice that the articles usually have one or two experts quoted, so you think about who you might interview for the piece. And they usually also include a dramatic story involving a senior. So you put all that together in your query, which might read like this.
"Shirley Smith, 70, was nervous about living alone. But she was surprised and pleased to find out that painting her house pink was an inexpensive and effective way to deter potential burglars. Not only that, by adding garden gnomes in a particular pattern, she made her home even safer. Home safety expert John Jones recommended these and five other budget-friendly ways to make your outdoors protect you and your home.
I've been a police officer for ten years and have seen many of the mistakes people make in trying to keep their homes safer. I'd like to suggest an article for Old People Magazine that would share tips from John Jones and from retired burglar Steve Saunders on how to deter criminals without spending a lot of money. I expect the article to run about 800 words."
Then you'd close with a polite salutation, and email it off to the editor. Don't mention, by the way, that you haven't had anything published before! Just stress the aspects of your background that make you the right person to do the article.
While you are waiting to hear back, put together the next query to the next publication. (And don't forget websites - some do pay!)
There are lots of courses you can take to get started in writing, as well. Paul Lima, a Canadian writer, has some good online ones (just google his name) and some inexpensive e-books. Your local college might offer some too. Or look for a writer's group to join.
Hope that helps! I love writing!
Teresa
