Tension is a controlled dramatic or dynamic quality in an artwork. There is a balance between and interplay of conflicting elements.
Tension can be created through:
contrast - light and dark, large and small, curves and straight lines. The greater the contrast, the greater the tension.
angular lines which typically carry more tension than either horizontal or vertical lines, because they are perceived as less stable.
asymmetry - as it creates unbalanced forces on elements within the picture frame.
pushing against motion - where one object appears to be pushing against another.
using the lightest lights and the darkest darks at focal points.
uniting some elements so that they become held in, almost framed, so what lies outside the frame appears isolated. This creates a push and pull, a longing toward unification. Imagine a cityscape with groups of people walking, if placed well, the lone figure will seem released from the pack - the group dynamics will create tension, both amongst the connected people and between them and the lone figure.
opposing forces - including brush strokes which run in contrary directions, rather than in the same direction.
apparently breaking the laws of physics - where an object looks suspended in space, or appears to counterbalancing a larger or heavier object.
Paul Cezanne, Compotier, Pitcher, and Fruit (Nature morte), 1892-94
The most obvious example of tension in this asymmetrical painting by Cezanne results from his use of opposing picture planes - whilst the background appears to be quite natural both vertically and horizontally, the table holding the fruit is at an odd angle, and the fruit appear as if they should be rolling down to the right, off the table. Note also the way in which the white fabric appears almost suspended against the bowl suggesting either a very stiff fabric in contrast to the soft folds of the fabric at the back of the table and the curtain.
Cezanne typically created space and depth of perspective by means of planes of colour and shape, which were freely associated and at the same time contrasted and compared. This created not just one but many perspectives.
Note also the way he used the brush - working in different directions, creating patches of colour, with the strong bright colours in the centre and muted colours framing the objects on the table. He has used similar tones as a way to create this frame.