Line is present in every photo, and is often used to guide the viewer's eye around the image. Line can be used for a vast array of different things, showing shapes, convey feelings, moods and defining space. 

Shape is a 2D enclosed object contrasted by its surroundings or defined by a line. 

Form is a 3D shape or object. 

Space is the area around the subject of the photo, commonly referred to as negative space. Space can be used to emphasise the subject and make the photo more interesting. 

Colour is the way light reflects off of an object. It has three aspects: Hue – The name of the colour. Saturation – The purtiy of the colour. Value – The lightness or darkness of the colour. 

Value is the measurement of the gradient of lightness and darkness in an image. 

Texture is the way something feels or would appear to feel when you touch it. 

Typography is the way text is arranged within an image. 

Balance is the overall composition of the image, and if it creates a sense of equalness in the image. Balance comes in many forms such as radial balance, horizontal balance, vertical balance, formal balance and informal balance. 

Contrast is the difference between elements within an image and creates an added sense of interest in the photo. 

Emphasis is the use of making something in the image dominant in order for the viewer to focus on it more. Values, colours, shapes and other elements can be used to create emphasis within an image. 

Repetition is the act of repeating shapes, objects and elements within an image to create a sense of activeness in an image. Repetition can also create a feeling of movement or harmony in an image. 

Movement is the act of using elements within an image to show movement, action and direction to guide a viewer's eye along the image. 

Rhythm is the reoccurrence of elements within an image to create excitement and make the image look interesting. 

Scale and proportion is the relative scale size of objects within an image and can be used to create really interesting illusions within an image. 

Variety is the use of different objects and differences in objects within a photo to add interest. Variety can be made by using strong contrasts between objects such as shape, size, texture, colour, etc and opposites such as straight lined objects and rounded objects. 

Pattern is the use of repeated objects and elements within an image to create a feeling of repetition and planned placement. 

Volume is the weight felt and held by a subject and its composition in the image. 

Unity is the feeling of the whole image being unified together as a whole and following the same theme. Unity is made when the image feels connected between the elements and objects in the photo.  

Harmony is created when everything within the image makes it feel connected. Images with harmony create a feeling of togetherness within the image's elements and subjects for the viewer.