Before we get into your homework exercises, I want to make a few things very clear:
Do not grind. Complete the recommended amount of each exercise to the best of your ability and move on.
Do not rush. Give yourself the time you need to plan your lines out, to prepare appropriately, and to demonstrate your current best.
Read all of the instructions carefully, multiple times if necessary. While I've tried to organize this content in as digestible a manner as I can, there is a lot of information here and there is no way you'd absorb all of it at once.
Take breaks! One day you're going to be a beast who can draw for hours without breaking a sweat, but right now, you need to be patient with yourself and take it all one step at a time.