My rule of thumb is you’re as good a writer as your last clip.
So find an editor, any editor, and start pitching business stories. If you’re really starting out, and don’t have *any* clips at all, go after the Pennysavers and the like — do some profiles of local businesses. The pay is pennies per word. But write the stories well and you’ve got yourself a clip. Then you try local weeklies, regional business pubs, suburban dailies, trades, big city dailies, then national business mags, in that order.
Get a frank assessment from somebody cruel as to where you are on that foodchain, based on your writing and reporting ability. Then call the editor you want to write for, and ask for a few minutes to come in and show him/her your resume and clips and chat about what you can do for them. (This of it as your standard sales call.)
If you’re wrong about where you are on the food chain, and you’ve aimed too high, ask the editor to recommend other markets that might be more appropriate for you. Ask the editor to name names, then recommend people to talk to at those publications. Then follow up.
You need a niche. The more specialized, the easier it is to sell the first article. (Then, once you’ve made the first sale to the pub, you can branch out to other topics.) For example, I write about financial services technology. Once I pitch a tech story to someone, I often find that I’m asked to write about other topics, as well, that the publication is interested in.