Double Exposure is when two images are combined as one. Black & White is when the picture is in black and white instead of the original color. Sepia is when you tint the black and white picture. Emphasis is where your focus is on one point because that is the only thing that has colors. Boat 'n' hand is an illusion that happens at a perspective so it looks like something that would be impossible. Silhouette is when the sun makes the other side of the object darker. Rule of Thirds is where you take a picture where the main point of focus is either on the intersections or in the middle square.
My favorite element is Perspective. My favorite Principle is Rhythm/Movement.
Elements & Principles link!