Hello there!
To answer your first question, the answer is no. The re-take exams are there to offer you the opportunity to better your exam scores, if and when you see fit. They will not negatively impact you in any way. Don't be afraid to utilize that option. I for sure use it when I need it.
As far as note taking goes, it will begin to come more natural to you when you find out what works for you. If you want you can look up different note-taking methods. Personally, I loosely follow the outlining method. That is just what works best for me. My tips for you would be to take down all main themes, anything that you think may be important, highlighted terms and their definitions, and names and important dates.
You can opt to print out digital study guides and online Textbooks. If you do this you will be able to highlight, take notes in the margins, and use sticky notes. That is what I sometimes do.
If you want you can also check out these discussions:
Helpful Resources Right Underneath our Noses
Also I would recommend checking out Ariel's blog. She has some fantastic Study tips:
I hope that this helps you! Best of wishes.
17 and Under Manager &
2016 Student Ambassador