Camera Aesthetics/Composition
Every story has a structure; a beginning, a middle, and an end. A movie or a TV show can be broken down into acts; acts into scene; scenes into shots. WHEN SHOOTING, ONLY INCLUDE THINGS THAT ARE IMPORTANT TO THE STORY. These are tips to help you shoot.
Rule of 3rds
Mentally divide your frame into 3rds, vertically and horizontally (like an imaginary game of tic tac toe). Place your points of interest where the lines meet. This is a simple rule that works pretty well.
Head Room
Head room is the space above a persons head within the frame. When you shoot someone, it's a good idea to place her eyes on the top 3rd line. The eyes, the main thing you look at when someone is talking, are in the middle of their face. Placing the eyes on the top 3rd line is visually pleasing. By giving someone too much head room, you are not making the best use of the space within the frame. This is a really common mistake for first time shooters.
Lead Room
By placing the subject on one of the vertical 3rd lines, you are establishing some lead room by leaving some space to the side of the subject. Psychologically, this is easier to look at because your subject don't look all cramped in.
link to video
180 Degree Rule or Crossing the line
The line is known as the axis of action. It's an imaginary line that determines the direction people and things face when viewed through a camera.
One way to think about the 180 degree rule is to pretend you're taping a football game. Team X is trying to get a goal on the left; Team O is trying to get a goal on the right. If you move the camera to the other side of the line (the other side of the field), Team X will look like it's trying to get a goal on the right and Team O will look like it's trying to score on the left. Confusing, isn't it? Both teams look like they have reversed directions - but they haven't moved, the camera did. To avoid confusion, stay on one side of the action.
In other words, when using the 180 degree rule, you are drawing an imaginary straight line between the subjects and staying on one side of the line. If you were to turn this picture upside down you would see what I mean. Eventually you will want to cross the line. You can do this without confusing the audience by stopping on the line, and then crossing. But hey, sometimes you want to confuse them, like if you are making a horror film. Crossing the line is a great way to do that.