A piece of advice: whether you suddenly get a brilliant idea while sitting in class, or are thinking about all the things you need to do tomorrow, and the next day, and the next day...
WRITE IT DOWN!
Writing things down as you think of them is a great way to stop having to worry, and to be able to come back to some things when you have more time. You think you might remember it in the morning or later on, but you might not! So write things down and clear your mind :)
