As I mentioned in my post about seeking outside inspiration, contrary to popular belief, new ideas do not come out of thin air. They come from learning, exposure to new things, and active brainstorming and thinking as a practice and as a way of life.
One particularly fun and helpful practice is to collect things that inspire you and surround yourself with them. Find photographs, artworks, objects, phrases, articles, and music that you like and that challenge your thinking. Figure out why you like these things and then use your collection to source new ideas. You could store your collection on your shelves, desk, your walls, in files on your computer, and all of the above. Whatever it is and where ever it exists, have fun and make your “inspiration collection” work for you.