I would like to try e85. Is there anything special I need to do?

Does it have the flex fuel system? If so just fill it up. That's it! As for the percentage of fuel (?) Test kits available!

There should not be any special considerations. Having said that if you are going to be using this type fuel for a long time you should stay with manufactures specified weight/viscosity oil in a synthetic or synthetic blend. You should also be prepared to get between 15% and 20% poorer fuel economy. 1gallon straight gasoline has more energy than Gas that has 10% ethanol. Gas with 10% ethanol has more energy than E85 fuel.