Slowly phase out your graphic and super sparkly tees.
Invest in some nice shoes that were not made by Mudd, Rocketdog or Sketchers.
If you're a girl, your shorts and skirts should not stop where your butt meets your legs. Length is a consideration on skirts and shorts. Your tummy should not peek out from every outfit you own because the pants are low-waisted and the top is cropped just ever-so-slightly. Wear clothes that fit.
If you have a chance to go to Europe or travel abroad before you start working, DO IT. Until you retire or have a nervous breakdown, you won't have more than 2-3 weeks vacation at one time for the rest of your working life. It is worth the debt.
Speaking of debt: get a copy of Suze Orman's "Young, Broke & Fabulous." Read it. Love it.
Buy a basic cookbook of simple recipes. Get a first-aid kit and an emergency road side kit if you don't already have one.
Buy a AAA membership.
Go to Vegas. Get it out your system. After you wander the strip drunk for one night, you'll start to wonder what the big deal is about Vegas.
Repeat after me, "The weekend starts on Friday night." Happy Hour or a glass of wine at dinner is fine, but don't come into work hung over or smelling like a liquor cabinet. Thursday night is not the new Friday. You can get fired for not giving 100% to the job.
Graduating from college does not entitle you to a 6-figure salary and the corner office. Unless you're working for your dad and your dad's last name is Trump, Gates, or Spielberg. You're about to start at the bottom of social totem pole and the first rung of the working ladder. Show respect, be on time, take notes and be proactive.
Always keep your resume and work portfolio updated so that in the event you have to leave your job or find a new one you waste no time.
Join a professional organization and get involved with a planning committee. IE: Business Marketing Association, Society of Automotive Engineers, etc. Great networking and your boss will love the ideas you bring back to the office.
Register your changes of address with your GLO. Join an alumnae/alumni group.
For the love of all things holy: DO NOT GO BACK TO THE SORORITY/FRATERNITY HOUSE DURING RECRUITMENT, SHOW UP AT CHAPTER MEETINGS UNANNOUNCED OR OFFER YOUR ADVICE TO THE CHAPTER UNLESS THEY ASK FOR IT. It is no longer your chapter-- it is your chapter of initiation. Let the members and their advisers do what they need to do and don't be a buttinksy. There will be plenty of opportunities for you to meet the new pledges, watch the recruitment skits or booze it up at homecoming. Don't become one of THOSE alumni/ae who can't let go of college. If you're missing your organization, get involved with an alum group. Write your chapter a letter wishing them luck with recruitment or drop off a plate of cookies and a note during finals. Do not concern yourself with the goings-on or what they're doing wrong. You don't pay dues there anymore and if alumni/ae need to get involved, the chapter will reach out to you.
Your bedroom and office/cubicle should not look like a loving tribute to college. A few framed photos are fine, or a university mug/pillow/sign.
Enjoy the post-college life! You've worked hard, and all year long as a senior you've been wishing you were done with school. But time does a very tricky thing. Six months from now, the stress of planning socials combined with acing finals and going to class will have been replaced with happy memories of intramural football games, winning first place at Greek Week and singing sorority songs. And you'll wonder why you were in such a hurry to be done with school! So enjoy this last year, take lots of photos and try not to skip out on too many meetings or events!