You can learn to write well. Writing is a craft that takes skill that is learned and practiced. The biggest piece of advice that can be given to a aspiring writer is, write, write, write. Start with the basic rules and practice your craft. Find your weakness. Is it grammar, is it spelling, is it punctuation or article structure? What ever it is, really study that area until you understand and can use it to your best advantage.
(1) Interesting Idea. Of course what is interesting is relevant to the audience for whom you are writing. Find a unique angle to an overdone subject. For example, the over done subject for a garden article might be "How to Grow Flowers" and an unique angle would be "How to Grow an Indoor Orchid Garden." Then you would go on to write an article specifically about the needs of Orchids indoors.
(2) Useful Information. If you are writing about a subject you know well you will be able to give an insiders point of view. The article will be all the better for it. However, even a subject you know will need some research. If you are ever in doubt about a certain detail, research it. You want to build a reputation of trust in your name as a writer.
(3) Sentence Structure. Always, always read your work over before presenting it. Make sure your work is grammatically correct, including spelling, sentence structure. One tiny overlooked error can make the difference in not getting the sale. In addition, structure your sentences using the least possible words. For example: "You will need to" should be changed to "You must." An article will seem as though it's dragging on if it has a lot of extra unneeded words. Tip: Don't forget paragraphs. It is very difficult to read a big blob of words, 50 lines long.
(4) Three Parts. An article should have a beginning, middle and end. The first paragraph or two is used to introduce and give an overview of your article. The middle, the longest part of the article, is the meat. If you are doing a straight "how to" article you will have all of your steps laid out in numerical fashion. If you are doing a more in-depth article like "How to Grow an Indoor Orchid Garden" you will want to have sections after the introduction such as, "Soil Preparation," "Transplanting," "Best Containers," Growing Location," etc. The ending should be short and sweet. Take a paragraph to write a closing that may include an additional tip or two. Maybe there's a warning you couldn't fit into another section.
(5) Resources. Additional resources are not always appropriate; but, if there is information you think the reader might benefit from that is along the same subject line, it's nice to give sources at the end of your article. Tip: When deciding on what resources to include, go with an expert not a commercial site (unless the commercial site as in-depth information).
These steps should give you the confidence to start writing. If you are just beginning, open an account at Squidoo or Hubpages. After you have a few good "clips" under your belt to show prospective employers, apply for paying markets. Free Lance Writing Gigs lists available writing jobs every morning. It's a great place to start your search.
Additional Resources