1. Take the opportunity to do a couple of test drives at different times and different conditions See how you like the seating position, inside space, and the shifting pattern - both automatic and manual.
2. Bring along anyone you might normally ride with and have them sit in the passenger seat to see how comfortable you both are with both of you in the car.
3. Check out the storage in the back. A luggage store owner suggested taking home a new piece of luggage and packing it with a normal trip's worth of stuff before you need to take it on a trip. If it doesn't work bring it back. That's good advice, if you like lacrosse, see if your gear will fit.
4. Drop in on any local Smart gatherings and chat with other owners while you are watching the forum for thoughts, ideas, and information. I'm sure they'll love to share their experiences. You'll learn all the little quirks of the car, especially when you find people like yourself.
5. Prepare to have fun.