1. Explore nature. Go outside and see things. When was the last time that you had time to stand and stare at the sky? Nature can be a good inspiration to you. For instance, Newton had to see falling apple when the concept of gravitation triggered his brain.
2. Exercise. If your body is fitter, your mind will perform better.
3. Read books that interests you. Think about every sentence that you read. Don't just try to cover many books but try to uncover the most from every book you read.
4. Start a fun creative project. It could be art, music, poetry, or even math and science. Imagine things and put it down in a way no one has done it before.
5. Socialize with people who have similar interest like yours. Have fun.