I've been going every year for the past few years, the last 2 years solo. The only thing I'd add to what's been said is that the anticipation of flying in is a whole lot more of an adrenalin rush than the actual flying in, which is pretty easy if the weather's decent. If it's marginal, and it can be, it can be a bit of a hassle. If it's IMC, you can't get in without an IFR reservation. ALL THAT IS IN THE NOTAM.
Do not, DO NOT, attempt to get without the NOTAM, and follow it religiously.
But some other comments:
One of my favorite pastimes is to sit on the flightline, watching people land. I have seen almost every kind of error that can be made, and most of them are because of failing to slow down and land on the designated spot. So practice a bit, just like you would practice for going into some short back country strip, so that you can set down where you want to, at the speed you want to, every time. It's not just the hot rod high perf Cirri and Bonanzas which screw it up, either--last year I watched a 172 almost go off the end of 27 (which is almost 6200' long), so close to the end that they got out and pushed the airplane back to turn it around to get to the taxiway. So get your airspeed down while on downwind--and practice with a very close in downwind, because that's what they want you to do, also.
They want you to exit as soon as your speed is down, onto the grass. I'm amazed at how many people stay on the runway to the next taxiway, with all sorts of volunteers trying to wave them into the grass, before they finally get the message.
Make sure your location sign is in the windshield before you land (see the NOTAM), if you go alone, or that your passenger has it ready to put into the windshield as soon as you're on the ground (and make sure your passenger doesn't block your view with it, like mine did one year!).
Otherwise, the only difficulty I've had was failing to put on sunscreen while milling around the camp area one day in 2011. Basic rule of visiting with other pilots: a 20 minute visit takes about 2 hours, and 2 hours in the OSH sun is 1 hour and 40 minutes too long!

The Seaplane base is a must-see, as is the museum. The Seaplane base is like going to Jimmy Buffet's place--very laid back and relaxing, compared to the hubbub of the Airventure grounds. The museum is truly fantastic, and some of the programs that occur there are well worth it--really enjoyed Bob Hoover's presentation one year and got to meet him afterwards (just one of many hands he shook that day)--I loved a couple of his comments: "I'm getting up in years--you don't mind if I sit down to talk, do you?" In answer to a question in the Q&A after his talk, if he's still flying much: "Oh, I like to take the Extra up 3 or 4 times a week, just to see if I still know how."
Vendor food is plenty OK, and no more expensive than vendor food anywhere else--and it's handy. There are several restaurants just outside the grounds--Friar Tuck's is a favorite, with good food and service, and LeSure's across the highway from Friar Tuck's has excellent breakfasts.
The outdoor movie at night is fun--but take bug spray, and a light jacket.
Incidentally, my "cure" for the bugs has been the OFF! fans the last 3 years. I go through several refills and batteries in a week, but it sure makes sleeping a lot less annoying.
Cary