The frequency and speed of the wind
The energy of the waves hitting the shore
The hardness of the rock that makes up the shoreline
All of these will determine the shape and how fast a cliff is formed, such as the speed of the wind and water, as well as how hard a rock is, will shape how the rock looks like.
For example, if the wind and waves are traveling extremely quickly, and the rock is made of sand, the rock will break much quickly.
Hope this helps
