Tone/value and colour
Have a tonal plan/value structure and stick to it. The eye will go to the spot of highest contrast. This is a good place for saturation, in keeping with the value structure that you’ve figured out. Many people confuse saturation with value. Saturation is the purity and intensity of a colour without dilution with white. If every colour is saturated then the eye doesn’t know where to go. Add a desaturated area in the middle of a saturated piece and the eye will go to the desaturated area first. Invert the formula and it works the same way.