Things you can do outside of studying to help with your academics:
Read fun things
Exercise. Run, walk, kayak, go to the gym, do yoga, something.
Eat nutritious food
Eat fun food
Get good sleep
Drink water
Go out with friends
Take vitamins if you need them
Keep healthy relationships and regularly do checkups with the people you keep in your life
Listen to enjoyable music and podcasts
Have a you day once a month
Constantly remind yourself why you live life and learning
By taking care of your body and mind, you will be able to succeed better. Don't let classes keep you from living life. If that happens, you will suffer and thus your grades will too.