
From composition to lighting to technique and everything in between, you can really learn a lot from just looking. Try to dissect the photo and discover what makes it interesting to you. Is it the subject matter? Is it the colors? Is it the amount of contrast in a black and white? Is the subject cropped in tight or small in the frame to give a sense of space.
There's an endless amount of great photos on the web. Try to set aside some time each day to just look at lots of photos. Remember to do the other great thing to improve your photography too...take lots of photos!