Often times as amateur photographers we are often taught to shoot with our main light source at our back. This enables our main subject to be lit from the front side, or front-lit. It makes exposing for the scene an easier task and that's why it is often suggested to amateur photographers.
As you grow your ability and creative vision, I would suggest trying exactly the opposite and shoot directly into your main light source causing your main subject to be back-lit.
This is generally harder to expose for, especially depending upon how you have your camera set to meter the scene. Generally the camera tries to over-think this situation and your pictures come out darker than they should. However, once you to learn to control that by using your exposure compensation, or another light source, such as a strobe of speedlite, the results can be something to be proud of. Today, I specifically wanted to talk to you about silhouettes. They are really quite simple to achieve, but I'm asked how to get a good silhouette on many workshops I teach. The first thing you need is your main light source behind your subject. Then if you want your subject to be silhouetted, dial your exposure compensation down to -1, or in some cases, -2.
The image below was created just that way. I had my subject get between my camera and the light source, in this case the sun. I dialed my exposure compensation down to -2 and fired away. Another tip...I set my aperture to F/16 to get that nice star burst from the sun. A smaller aperture (bigger number) will give you more of a star burst effect