The amount of space in the frame left around the character should not be left to chance.
You should try to leave more empty space on the side towards which the character is moving or looking.
The height of the face relative to frame is also important. Compressing the space above the head will create an atmosphere of tension and drama, while leaving too much space above the head, gives the impression the character is sinking. The eye level should be placed at the top third of the frame‘s height.