The tips begin at a different place in each module. The advice moves along with the stages of the course.
Physics and chemistry formulas aren't plug-and-chug machines. A formula lays out the terms of reference. What changes with what. In addition to being a tool to solve quantitative problems, a formula is a conceptual window into the system. What are the correspondences between quantities? What are possible changes in the system the formula describes? What changes? What stays the same? Formulas!