First choose what to photograph. Almost everything can be silhouetted, but some things look better than others, so choose your subject wisely. When you have chosen, make sure the light is shinning from behind the object. Make sure your flash is turned off. I took these pictures with my iPhone. By touching the screen in different places, I found the perfect focus and exposure. This will make the subject become very dark or even black. If you think your silhouette is not dark enough, you can always make it better by adjusting the contrast or adding an effect.