Highlight - adding a lighter colour or white to another colour.

Shading - adding a darker colour or black to another colour.

Blending - using your finger to mix colours together.

Feathering - making a line by pressing hard and pulling away.

Pointalism - making dots.

Scumbling - scribbling with the chalk.

Hatching and Cross Hatching - parallel lines that cross over each other.

Scraffitto - using an eraser to create details in the chalk.