Just because you are a writer doesn't mean that you are going to sell your articles. You have to be the best salesperson that there ever was. You have to sell yourself to the market.
How do you do this? First of all, you have to locate the market that you want to sell to. If you are a non-fiction writer, then you should look into some magazines that buy non-fiction. If you are a romance writer, look into magazines that buy romance writing.
The Writers Digest publishes the Writers Market book yearly. You can also get this publication on line for a nominal fee. You can subscribe to their magazine, which lists markets. Another helpful publication is The Writer, which also publishes markets and their guidelines. If you are a children's writer, you can also locate the Children's Market book. If you are a Christian Writer, then there is a Christian Writers Market book.
Libraries often have copies of these books, so you do not have to purchase them. Also, the libraries carry copies of these two magazines.
After you locate the market you want to sell your work to, you should see a copy of the magazine/book itself so that you know exactly what they publish. If you cannot locate a copy of the magazine, ask them to send you a sample copy. Look it over and see how you can work your article into their format.
After you see the sample, look into getting their guidelines. You do this by a query letter, selling your skills/talents to them. Most magazines have a schedule of themes for particular months of the year. Magazines operate on a yearly schedule, most of the times. For example,if you are submitting a Christmas article, this would have to be done a long time in advance of the December issue. Sometimes you can query with your article idea and see if they are interested in that subject. Guidelines can be obtained on line, so a copy of the above mentioned books will give you the email address of the company that you are seeking.
Do I submit on line or by mail? This information will be supplied in the guidelines. Be careful to follow instructions. So many good pieces are discarded by editors because the writer does not follow instructions.
Query letters will be discussed in another article, so please look for it.