This document provides tips for conducting lean user research as an entrepreneur or product manager. The five tips are: 1) Know what you are testing by determining if the question is about the user or product; 2) Know who you are testing by specifically defining the target user; 3) Know which corners to cut by utilizing quick research methods under an hour; 4) Know what to do with results such as capturing observations and prioritizing findings; 5) Know the unanswerable questions like would users buy or pay without concrete experience. Following these tips helps focus lean user research on answering key questions.