Advice
Be prepared to dive in headfirst - the phrase "getting thrown in the deep end" sometimes doesn't do it justice; I felt like I'd been thrown in the deep end and held underwater for the first week or so. It's overwhelming, but it was also insanely beneficial to my growth and my learning. Know that the deep end is an okay place to be, and learn to handle that overwhelmed feeling so that you can thrive under pressure. (There's an A+ TEDTalk about handling stress and responding to stress with a positive attitude - Kelly McGonigal, go look it up, it's seriously worth the time, it'll help in your academic career, professional career, and personal life!)