Format means whether a picture is portrait (vertical) or landscape (horizontal).

Portrait

Landscape

The perspective of a photo is the angle in which it is taken – eye-level, from below, bird’s-eye view, etc.

Foreground interest is when your main focus is in the foreground of the picture with another object in the background.

In this photo, the lines of the corridor and the banister converge into a point.

Here, the gaps in the bench form lines that travel towards the bag.

The balance here is between the tall building on the right and the sky on the left.

Here, the subject is on the border between two thirds.

In this picture, the green background is bare, letting the bag attract the eye. The background isn’t cluttered, meaning the subject isn’t fighting for attention.

The woman here is framed by the wooden post and the bin, while in the photo below, Louise is framed by the table legs.