I used to never study and pulled 85-90%. Then I started engaging myself more in class and studying before tests, etc. and I managed to pull that up to 92-98%.
So it does help also, asking lots of questions until you're 100% sure you know what you're doing. Teachers are paid to make you understand, so don't feel bad if you have to ask and ask and ask, even if it's the same question (or similar). Their salaries depend on it lol
Also, going back to the burn thing two pages back, you're actually not supposed to run your hand in cold water. It aggravates the burn even more. That's what they teach you in First Aid training.