school of athens utilizes many renaissance techniques such as perspective, realism, and uses renaissance concepts such as the appeal to classical philosophy and sculpture.
firstly, the entire painting is a tribute to classical philosophers such as aristotle and plato. roman architecture and greek gods' sculptures can also be observed. among the classical greats, raphael (the high renaissance's youngest master) making a tribute to other great renaissance artists, such as his master michelangelo.
artistically, the piece paints itself as a prime example if renaissance techniques.
you can see the use of perspective (the artistic illusion of space and depth), as how the people and environment get bigger the farther you get from the center (in this case the center is the vanishing point.)
the use of realism (lifelike) can be seen in the figures' anatomy. their positions and humanly elements such as muscles and skin are quite realistic. a touch of naturalism (focus on nature) in the accuracy of the sky and clouds in the background.