One can look at someone and determine their structural and physical flaws: height, clavicle width, bow legs, waist width, muscle inserts and lengths. Then there's one's response to training, nutrition, and PEDS. Olympians like Yates, Cutler, and Coleman notice from the beginning that they were naturally much stronger than everyone else in their gym. Some like Levrone and Health notice that their response to training was above average. They noticed that they just blew up faster than everyone else and even more so when they started using PEDS.
One has to be brutally honest and make an objective evaluation as to where one stands.