Here's some advice for those who don't know exactly what they're doing on a campus full of people who seem to. (Looking at you, Class of 2015.)
The Gym
The first time I stepped into the gym (not including for my belly-dancing P.E. class) was the beginning of my freshman Winter. I quickly realized that I couldn't pretend to jog around Occom in early January, so I decided I had to find a treadmill somewhere, somehow. First piece of advice: Never wear a long-sleeved shirt and leggings to the gym. Ever. Second: Always bring your ID. Even though you're sporting a Dartmouth quick-dry shirt and Dartmouth cap, you're with someone sporting a Dartmouth ID, and you're clearly 18-22 years old, the desk person will demand you have identification. Lastly: there are all kinds of strange opinions about gym etiquette floating around this campus. "Don't wear spandex, don't run on the treadmill if you're only going to do it for 15 minutes, don't lift weights if they're under 10 pounds, don't work out every day from 4-5 p.m." I say bullshit. Do whatever the hell you want at the gym. It'll make it that much more entertaining for those bored out of their minds on the Stairmaster.
DDS
I used to love chocolate-covered pretzels and home-made rice krispie treats. No more. This is because I made the dangerous mistake of eating these goodies every day freshman Fall. Every single day. Now that you're in college, there is a virtually endless supply of everything from printer paper to toilet paper and you don't have your mom to tell you to control yourself. Thus, you need to remember to control yourself. Eat a variety of foods, even sometimes healthy ones. Exercise portion control. Try the salad bar. Really!
Mass Row
On your multiple-times-a-day trek from the River (I'm sorry), Russell Sage or Fahey-McLane, you will inevitably experience the potentially uncomfortable eye contact with people you met during Orientation, or on your trip section or in the Psi U basement. Sure, they were super nice and seemed super cool but you're not sure you should wave to them, say hey, or even smile. When in doubt, just do it. If you initiate any of these friendly gestures, they will either return them with excitement and consequently think you're really nice and cool, or awkwardly look away. In that case, you know they don't deserve your friendship (or were too drunk to remember meeting you).
The Library
I distinctly remember the first place I ever studied: in one of the comfy chairs with the wooden boards on third floor Berry. The sterile fluorescence of the consistently crowded floor turned me off though, so I've branched out since then. There's 2FB (radically different in size, noise levels and ambiance), the stacks (if you like to work in the library), Sanborn (if you like napping in intervals), the East Asia Room (never been there 'tis a small room, but there are those who love it), Baker corridor (on a sunny day), the Periodicals (if you don't want to enter Berry), One Wheelock, the Dartmouth Bookstore, the Sherman Art Library the list goes on. Be adventurous! Think outside 3FB (or FFB for that matter).
Getting Sick
If, God forbid, you do come down with a 10-week cold, a hangover, the flu or some other ailment, stay calm. I won't recount to you the details of my over-reaction to a stomach bug last year, but I will say it resulted in two unnecessary trips to DHMC and six unhappy days in Dick's House. The point is, whatever you have is probably not life-threatening. So, once you feel the onset of something in your throat, nose or other orifice, get to your bed immediately. Take a bunch of Sudafed, Advil, Tylenol, Aleve whatever drug best fits your symptoms and go to sleep. When you wake up and still feel shitty, don't panic. Watch some movies, read a book and (in dire instances) chat on the phone with your mom. You will feel better, probably in three to five days. Some people say I give bad medical advice, but I would argue that sound psychological advice is most essential.
You're inevitably going to receive lots of (often conflicting) advice during your college years. Some will tell you running in only a sports bra is obnoxious, others will encourage you to be audacious. Some will warn against consuming Reds, others will tell you there's no harm. I can't personally advise you on every one of these decisions, but I can advise you not to sweat all of these small choices too much. After all, most of us upperclassmen haven't quite figured out how to navigate this place either.