Read stories in the genre in which you want to write. Read other writers to spark your creativity, learn the elements of a good story and find your original voice. Read advice by professional writers who freely share their knowledge. Find techniques that work for you.
Take writing classes to learn the technical aspects of writing and get feedback from teachers and other students. If there are no classes in your area, join a writer's group. Listen when others read their work aloud to learn from their work. Accept their comments about your work as an opportunity to improve on your weaknesses.
Develop an outline that contains points you want to include in your story to help keep you on track as you write. The outline can be as detailed or as vague as you need it to be. Develop your characters before you start writing as well. Your stories will be more believable if your characters are well-developed.
Practice writing. Find time every day to write. Take 10 minutes before you go to bed to write if you didn't have time during the day. Write down some ideas you had during the day or complete a writing exercise. Work on your novel or write a poem. Just write.
Revise your work. Revising allows you to fine tune your story. Don't revise until you have completed a rough draft of your story. Keep the whole picture in mind as you revise. Ask yourself what is good for the story, not what you like the most. Cut out anything that doesn't work and clarify confusing plot points.