1. Write a genre that you feel comfortable writing eg. Sci Fi is quite common, Or vampire.
2. Plan the story in a mind map, or as draft version so you get a fair idea what it'll look like.
3. Start the introduction. Usually the first sentance describes one of the main chracters or their family.
4. Be descriptive. imagine the story is really happening so write down what you see, feel, smell, taste etc.
5. A good story ALWAYS has a good plot. In an exam or controlled assesment you will be given a title or the last line, or the plot. All you need to do is work around it. Be inventive and enjoy it.
6. If you ever need an idea, think of something thats happend to you or someone else, some people even watch a film or read a book for some ideas.
7. if you are really stuck, rewrite a book or film you've seen into a version you would like to see. (It would be adviseable to change the names of the charaters though. eg Don't rewrite twilight or harry potter with edward marrying bella or herry marrying ginny/hermionie/luna (PS i have seen the films and read the books so i know what happens. this is just for those that are yet to see the last harry potter movie)
(IF YOU HAVE ANY IDEAS I CAN ADD PLEASE SHARE. THANK YOU)