One thing which I do very often is isearching for some term, like a function or variable name. Recently I learned that Emacs has a nice feature which helps with that. Pressing M-s M-. (or M-s .) invokes the isearch-forward-thing-at-point command, which does exactly what you would expect. Very useful! In fact, pressing M-s
C-h reveals even more usefulness. Try it out for yourself!