Contrast

Contrast of values and contrast of colors will definitely direct the eye to a subject matter.  In this painting of a Friendship sloop, the sail is a warm, light value and its color is encased in a darker, cooler background. The neutrals in the background retreat so your attention stays focused on the sloop.

Try not to think in terms of subject, i.e. "I'm going to paint a boat and some water."  Rather, think,
I'm going to paint a warm, light shape surrounded by darker, cooler values.