An experiment: Shoot 20 pictures a day, every day. Of anything. Don't wait for inspiration, proper light, weather conditions, or the right human subject. Just shoot anything. Don't think about it too deeply. Keep them all, perfect or imperfect. (Download them daily; don't let them pile up.)
Do this for a month. Notice common patterns, colors, interests, techniques, times of day, faces. Select those that are more "successful," those that stand most strongly on the terms they set. Feel good that you were able to develop a theme or style.
Click any image to access the larger version on my flickr site. I honestly don't know that I have 20 images a day in me, but let's see how far I can take this. The current plan is to do 20 days, hence "the 400." Do please let me know if you see something you like (or hate.)