Not all sections of a surface are equal. Movement, space, and placement can be used to suggest time. Within the composition we can infer a sequence, a past, and a future. In part, this is due to how we read. Generally, we read top to bottom, and left to right. Within a scene in a painting we often interpret things happening at the top or left side as beginning, and as they move towards the lower and the right side, they are perceived as ending. Things happening in the lower right side tend to be perceived as happening later in time. Spacing and placement can also can suggest how much future or past there is outside of the immediate scene of the painting. This isn’t true for all paintings, but it does happen in some, and you can use it in yours.
For example, the painting Christina’s World by Wyeth suggests a moment of time in the subject’s future. We connect the figure (left) to the house (right), and the tension is in the suggested attempted movement from the figure through the blank space, as the figure pulls towards the house.
In the painting below by Harry Franklin Waltman, the action has mostly already happened (represented by the figure on the left), and the figure on the right is at his end. Both Christina and the fencer are in peril, but Christina, the figure on the left side, will extend into prolonged suffering, while the fencer, the figure on the right edge of the canvas, suggests the story is at its end.