Well, I'm a fictional writer and I get inspiration from random things. Sometimes I read a book and one scene inspires an entire story. Once I was on a bike ride and a plot twist popped in my head. I'll often lay in bed and think of a scene or chapter for my stories, and then write them down on a sticky note for the next day.
For you, what you first need to do is come up with a topic. There are tons of ways to do this.
1. Pick a genre. What's your favorite, or what do you feel you could write the best? Romance, Humor, Drama, Tragedy, Thriller, Mystery, Friendship, Fantasy, Adventure, Sci-fi, Western, Parody...these are just some of the genres to choose from. You can combine genres to make a really neat story with variety. For example, Romance/Drama is very popular. But, what if you were to throw in Fantasy or Humor? Or even Mystery? What could happen then?
2. Think about scenes. You don't have to come up with a base story just yet, but think about scenes to put characters in and their surroundings. Why is this scene happening? If you can come up with a few of these, sometimes that's all you need to spring a good idea.
3. Sometimes even thinking of characters can help. For example, if you think of a character who is dark haired and petite, very shy, but has a witty sense of humor, what genre/scenes would fit him/her best? Or what if you thought of the typical High School Hottie character, tall, dark and handsome, super charismatic, and every girl's dream, but all of a sudden every girl turns on him. Why did this happen?
4. Take cliched ideas and make them original. Remember that High School Hottie I mentioned in the previous tip? That sounded pretty cliche to you at first, right? But when every girl turned on him instead of falling at his feet, it may have got you thinking about why this happened, and what on earth could cause it. Try things like that!
5. Believe it or not, Fanfiction has totally exercised my creativity. Plot bunnies are springing up EVERYWHERE, and most of them could fit non-fanfiction works as well. Maybe you should try fanfiction for a while!
6. Don't try to force anything, just relax and take it easy. Creativity shouldn't be forced, and if it is, it will most likely reflect in your writing.
7. Go to a calm place, whether it be your room, a park, or a parking lot. Think. Write down events that could possibly occur wherever you are, or wherever your mind wanders. Turn on the radio. Think about how else could this song be interpreted. Write down a short story based off the song. Just write anything, and get your creativity going. Eventually, creative ideas will start coming much more naturally after a while.
I hope I helped you

If you want to read my stories, visit me at www.fanfiction.net/~swingdancer23. Scroll to the bottom to find my stories. Most of my oneshots (single-chapter stories) are very easy to understand, even if you don't know about my topics.
~swingdancer23