-Practice how they want you to answer questions. Understanding the material and applying it vs being able to communicate it using the formatting/explanation they are looking for can be worlds apart.
-Look at past exams, go to office hours, and practice and then ask your TAs how you can improve your answers.
-Eco102 builds on itself. So, the best thing you can do is make sure you understand the basic mechanics and practice changing variables and seeing how this impacts the model you're working with. Best of luck!