Welcome to the forums!!
1) 14 nights will be wonderful but don't make the mistake of thinking that you'll be able to see and do it all even in that full two weeks. Don't rush yourselves trying to do everything and end up making yourselves miserable and stressed. Just go and have fun. You'll be back again and can pick up where you leave off this trip.
2) If you are not used to theme park walking I would suggest going out and walking several miles a day before your trip to get physically used to the walking you'll be doing at Disney. It can be a real shock to your system if you are not used to it.
3) Slightly offset your meal times from the traditional American meal times. This may prevent you from getting stuck in a really long line at the quick service locations or having to wait a long time for a free table at a table service location.
4) Get good walking shoes but get them several weeks before the trip. You do not want bad shoes at Disney and you do not want blisters that come from ill-fitting shoes either.
5) Bring a plastic bag (Zip-Loc) for your valuables on the water rides. Kali may soak you and the center storage compartment still allows a small amount of water to get inside.
6) Bring aspirin, ibuprofen, ect with you. They are very expensive in the parks.