High school is f@cking easy!
Simply do what you need to do and you will get through it with flying colours. I look back and can't believe some of the grades I got in subjects that I normally excelled at and enjoyed, simply because I slacked off.
I skipped classes. That was my downfall. Because I skipped, I didn't know when assignments were due and when we had tests. On several occasions I walked into class to be surprised by a test or due assignment.
Simply attending class would have helped me avoid doing an extra year of highschool to complete a handful of classes. The time I gained by skipping was simply re-paid during my extra year.
What a f@ckup.
One day I'll tell you about how I turned it all around. You'd never know I was the same person.