One of the many Calvin resources I found very helpful was the tutoring service. Back home in Nigeria, I grew up having 'lesson teachers'; people who came over to give extra lessons or help with homework. So having a tutor wasn't new to me.
I found it helpful because it was like purposely taking time out of the class period to go over what was taught in class. I noticed I always said I would do it, but never did unless I was made to.
Besides that, they give good tips on how to go about the class, because they most likely had the same professor.
They help with homework as well, so set time to do homework too and answer any questions you might have any time of the day.
It does help increase confidence in class, plus looks good to the professor that you care about their class & YOU MAKE A NEW FRIEND. :)