Ok here is my advice as somebody who is 3/4 trough the class and has been getting his balls crushed at every turn, even with a ton of reading, effort, and studying.
This class is about light, it is not about mineralogy. If you know what the light is doing you will be on the right track. The rocks don't even matter. All the rocks really are are tiny little filters to manipulate the light with. Just focus on the light. You wont have to identify anything till at least half way through. This would have helped my first half of the semester. Nobody told us this, and I am still pissed about it.
Read the book, then read it again. Light is hard and its an asshole. Then cry, then read it again. If your book is anything like mine and it was written by some asshole autistic super physicist. I am still pissed about this. Most of this stuff can be explained in like 3 sentences in plain english. But Nooooooooo Nesse (author) has to talk like an awkward autistic robot.
When you do the labs, don't just do them, you HAVE to understand and master them. Each one is a diagnostic test more or less. Each one is a task, and a skill, and you have to have a high proficiency in each of them. Its not like chem where you just mix green shit with blue shit and you get red shit "yay". When you get a high proficiency in each you can set the scope up and turn the stage a couple times while messing with the cross polar and the accessory plate and BOOM you just knocked out 3 or 4 tests simultaneously. Again, nobody ever actually said this in class. This would have helped my first half of the semester alot. I am still pissed about this.