photo prompts. i have a friend who's always posting random pics, so i decided to use them as a muse. study the photo for a couple minutes then look away. write down any words or emotions that come to mind...then go back to the photo and write a minimum of three lines to describe the photo. works for me.
If I may offer some advice, sometimes listening to music is a great way to get the idea juices flowing. I get a lot of my ideas from music, especially movie scores and classical music because they let you use your imagination more. Camille Saint-Saëns, John Williams, Alexandre Desplat, Danny Elfman, Alan Menken and Hans Zimmer are great, it's crazy how easy ideas get generated from that stuff.