Floating your brush to reduce brushmarks.

 The video is clumsy, but the technique is clear.  Drag the brush lightly across the fresh paint to reduce brush marks from showing the underlying layer.

This is an example of two things.  A) not always brushing in one direction.  The horizontal lines are from the first coat of paint.  B) Layers of paint too thick. Brush marks are exaggerated.

Thick coats of paint are more likely to peal in the future.