Formal elements are the main components of any piece of art, they are line, tone, shape, texture, pattern and colour. Their combination results in works of art.
Lines are the simplest aspect, they are the continuous application of a colour from point to point and may be short, long, straight or curved. They lend structure to the artwork and are typically the first element used.
Tone is the application of light and dark and can range from lighter or darker colours to shadows and highlights, they add depth and lighting to artwork.
A shape is a bordered area of colour, though they may be gradients and change colour they are often distinct from the background and usually rely on lines as their borders.
Texture is the appearance of the surface of something in the artwork, this is often conveyed through the medium the artwork is created in, though can also be demonstrated using different patterns.
Patterns are repeated combinations of line, shape or colour, they can be used in lieu of colour to add different tones and textures to shapes, the same pattern can be used on different shapes in more or less dense ways to create lighter or darker areas.
Primary colours are red, blue and yellow. Secondary colours are each combination of two of the primary colours, making green, purple and orange. Tertiary colours are created by combining the primary and secondary colours that are closest to each other on the colour wheel (below).
Below are examples of tone and pattern I created using charcoal.