This class is a lot of work- there is a 45 minute lecture at the beginning of class, and then the rest of the class is the lab itself. How you do really depends on the TA you get and how he/she grades you relative to the other people in your class, since they grade your quizzes/lab reports/everything else, and the grade you get is based on the curve in your individual TA section. My TA wanted a separate "clean-up procedure" section in the lab notebook write-ups, even though that isn't asked for anywhere (that I saw)... go to your TA's office hours and ask if he/she wants something more than the directions ask for.
It really makes no difference how hard the quizzes might be or how low the quiz average is, since you are curved based on how you do relative to the other people in your specific TA section. So if the quiz average is low (like a 10/20), that actually becomes a good thing, since it's not hard to get the average if you have an idea and are on the right track, and the class is curved to a B+/A-. If you want to do above the average... go to Rosa's office hours. She writes the quizzes, and will take the time to patiently explain specifics about the reactions to you, and make sure you actually understand them. The lectures can seem rushed sometimes, but that's because there is so much to cover in 45 minutes (and Rosa knows that). She genuinely wants you to do well, and will meet with you outside of office hours if you can't make it. I had a really positive experience because I made the effort to meet with her... if not, the class would probably have been a lot more overwhelming.
The lab reports take a lot more time than you think, so start early. Also, bring your mechanisms to office hours and ask your TA/Rosa to check them before they're due. Same with the pre-lab questions, and IR/NMR data you will turn in later... don't lose points when you could just ask.