How do you measure your performance?

Performance is the behavior of a variable (or many) over time. Achieving set goals or targets is, strictly speaking, not performance. Actually the best way of measuring - and improving - your own performance is to a) know what your performance stakeholders (customers internal/external, society, colleagues) require from you b) examine the processes you use to deliver these outcomes (are these capable, and are these statistically stable?), c) improve these processes. Measuring performance is addressed in b). Unless you know the processes you use to deliver outcomes, you cannot truly measure your performance.