Hi, I usually write out all my notes in a jotter at home and then go over some excercises in my textbook. The key I find for my is too practice. It may seem silly but I find that youtube has really helped me! There are lots of tutorials and people on there who can help you! Attend all support classes in school and always ask questions in class. You could mabye also study with a friend. Also desinate about 45 minutes to roughly about an hour for maths. Practice everything until you know it like the back of your hands. Also, once you know a topic remember to recap it every couple of weeks and months just so its fresh on your brain and on top of your head! I also need a B in maths this year!
Work hard! Good luck, I hope you get that B!!!