Chem/Phys is usually the section that worries students most, because it mixes general chemistry, organic chemistry, physics and biochemistry, often in a biological setting. The good news is that it's very trainable: a manageable set of equations and reasoning patterns covers most of it.
According to the AAMC outline, the section is roughly 30% general chemistry, 25% physics, 25% first-semester biochemistry, 15% organic chemistry and a small amount of biology. Questions apply these ideas to living systems — blood flow as fluid dynamics, nerve signals as circuits, enzymes as chemical kinetics.
Build a one-page equation sheet and practice using each equation with units, not just recognizing it. Get fast at estimation and scientific notation, since there's no calculator. Then spend most of your time on mixed passages so you learn to spot which concept a biological scenario is really testing.
The most common lost points come from slow arithmetic, mixing up sign conventions, and memorizing reactions without understanding why they happen. A tutor can usually spot which of these is holding you back within a session or two.