Know your stuff! Do some research and read up on the history of Cenote. You can also ask some of the locals in Cancun. They will know a lot of information on the history of the area.
Prepare yourself. Going into this environment can be a chilling experience. The entry into Cenote is a vertical column of steps constructed by the Mayans themselves!
Check out the blood red, limestone stalactites. These stunning formations seem to ooze like water from the rock walls.
Look for the tree roots. The trees over fifty feet above have dug deeper and deeper into the soil looking for the life sustaining water.
Go early! Cenote gets busy as it is a popular tourist attraction.
Take a tour. There are many tour companies in the Cancun area.