Dig through your old stories and articles and read them. Did you find a few that weren’t published? What have you learned that could make them better? Apparently, there was something that made you want to write them in the first place. Can you see any obvious short comings?
If your answer is yes, begin revising. Most of your hard work has been done. Getting a story/article down on paper is often the most difficult part. In under an hour or two you may have a publishable piece.
If your answer is no, read the piece twice and set it aside. Try writing it from another point of view or rewrite it. You may create a better piece than before.
Do you have any novels or books that have been started, but stalled and died? Read them twice and set them aside. Try writing an outline. Can you plot the remainder? Follow the same tips as you did for your stories.