1. To get back in the habit of cafeteria-style dining, stop letting your parents prepare just one dish for dinner. Make them create an array of chicken, pizza, yogurt, bagels, sprinkles, eggs, croutons, fish sticks, cakes, cookies, burgers, deli meats, and of course, tacos. Get yourself a serving platter and just load it up. For extra acclimation points, take a backpack down to dinner with you and fill it with snacks for later. And, while you're at it, steal the platter.
2. Pre-game in your room before crashing that high school party you heard was going on down the block. They're probably only going to have stupid, young-people drinks, like vodka that you need to swig right out of the bottle. That hurts your esophagus and makes your tummy feel a little meh, so you might as well raid your parents' stash and get yourself going on the good sh*t: California's finest Turning Leaf White Zinfandel. To make it really feel like you're back at school, wander through your house-bottle-neck clasped between your thumb and forefingerasking your parents and siblings if they want to get crunk in your room while watching The Wire illegally online. You might want to ask around about snagging a bottle opener too.
3. Wear flip-flops in the shower. If the fact that all the germs in there are yours is ruining the illusion, feel free to go down to the public pool and shower there (don't forget your soap caddy). The important thing is that you reacquaint yourself with the fear, anxiety, public nudity, and phantom toe itches that are such a vital component of all college bathroom experiences.
4. Practice reciting your social security number at all stages of inebriation. Should you ever find yourself in trouble at college, the answer is always your social security number. So when you're getting drunk with your parents, ask them to quiz you every hour. It'll be just like that time they helped you study for your Spanish final in 6th grade, but with less alcohol.
5. Start setting your alarm clock to get yourself back in the swing of waking up to an awful sound. Of course, it's summer, and you have no reason to wake up except to eat, and being awake will just remind you of the pitiful waste that is your life. So, you know, set the alarm for 5pm. That way you can snooze till dinner. Or September.
6. Buy $200 worth of books. Don't read any of them. Bemoan the fact that you just blew 200 bucks unnecessarily, but realize it would suck more if you actually had to read the books. Think about the contextual irony of your tuition. No, I take that back. Whatever you do, don't think about your tuition.