Tips for 100mile ride

bring food and water...
personally i avoid gels...def. try them out before the ride if you want to take them, cliff bars are my favorite and they aren't too big...always try what ever you intend to eat before the big ride so you know what its gonna be like on the ride as for water i recommend 1/2 Gatorade 1/2 Water and the biggest bottles you can fit on your bike...and definately 2 bottles I just got back from a training ride of a little less than 100 in 20-35 degree weather and I made it through 3 bottles of water and needed more

bring a tube and the sutff you need to change a flat...
its really really annoying (at least for me) to have to ask for help, C02 cartridges are good, look for steel body tire levers or have plenty in case you brake one

pack an after century kit...especially if its your first one...
you'll want food, water/energy drink, and a change of clothes because the sweaty kit is really going to be nasty if you have to spend much time in it after