The type of wave
Destructive waves cause more erosion than constructive waves.
Backwash is more powerful than swash.
More materials are carried away from the coast than are deposited on it.
Position of coast
Coast are not protected from prevailing winds are more exposed to wave action than sheltered coast area
Natural of coastal rock
Rocks that are made of different resistance to erosion depending on the mineral composition of the rocks and the presences or absences of lines of weakness.
Coasts made of granite and basalt( hard rocks) are more resistant to erosion than shale and clay (soft rocks)