The tips begin at a different place in each module. The advice moves along with the stages of the course.
Some sciences topics are high yield because they show up very often on the exam, such as fluid mechanics, geometric optics, or the protein laboratory. Some topics are high yield because they are at the foundation of science, such as atomic theory or the first law of thermodynamics. Some are high yield any way you choose to look at it, such as Gibbs free energy, electrochemistry, or enzyme kinetics.