One thing I've found to be fun is working with those scenes where the light comes from behind. It can give you a fun silhouette. Here are some photos where the backlighting made the photo so much more interesting.
Playing with some self-portraits one day and tried this one. The light was coming in from the window and the room was rather dark. A little cheesey but just an example of playing around with lighting to see what you can come up with in your photos.
This was in Hawaii in 2010. I had just been learning about lighting and this silhouette effect. The whole time we were there, I wanted to take this photo. This happened the last night before we left. We went down by the water outside of our condo at sunset, I relayed my vision to my mother-in-law, and she snapped the photo for me. We had a lot of photos from that trip and I think this one captures the entire vibe of the trip.
Over time I've learned to purposefully look for these types of shots but there have been many times that they happened on accident. Sometimes it can be a happy accident so don't be so quick to delete photos that don't turn out exactly as you wanted. Look to see what you can make of it first. You might find a good one that surprises you!
Feel free to share links to some of your favorite silhouette photos in your comments. Enjoy!