Look at the base of the cliffs and you'll see that I've painted the waves crashing up against them. The piece of coastline that inspired this painting has large waves crashing in, so there's a lot of foam visible to quite a distance. If you're painting an identifiable stretch of coast, this is the type of detail you'll need to obscure accurately for your painting to seem authentic.
I then turned my attention to the breaking waves, foam, and froth around the rocks in the foreground. This was painted by loading the brush with straight-from-the-tube paint, then dabbing the brush down tip first, rather than brushing from side to side.