wave drifter using arduino and accelerometer

Hello people!!
I am trying to make a sea wave drifter to measure wave height,wave periodusing arduino and acceleroneter. Some have suggested me to use gyrometer as well. I dont know to start with it.
I have a aurduino uno and adxl335 accelerometer. Kindly help me with this issue.

What have you tried? Do you have a library to talk to this sensor and have you installed it? Do you have the sensor plugged into the Arduino? Does the standard example included in the library work for you?