I wish I knew. Besides generic praise (like saying I'm a rockstar at my job) a few of my managers said that they loved how they could drop me into a situation with little to no information and have me come out successful. Other than that I really don't know how to measure myself. Sometimes I've pulled off things that other engineers said (to the product manager) were impossible; a couple times I've had humiliating failures that still make me sad to think about; most of the time I get my work done.