I spent more than an hour on each of these, thanks to endlessly switching out brushes and an unhelpful tendency to start in on details too early. (I'm going to choose something with less detailed faces next time in an attempt to combat that urge.)
1. Gentileschi - Self-Portrait as a Lute Player
The economy of the background lends focus to the figure. Within the figure, there are areas of detail and contrast throughout, but the movement of the gentle, repeated curves — the lute, her wrists, the folds of the fabric, the neckline of her dress, her décolletage, the wrap on her head, even her curls — serve as paths leading the viewer back to her face.
2. Leyendecker - Record Time, Cool Summer Comfort
(I tried to hurry myself on the left figure rather than spend forever doing details and attempting to replicate brushstrokes and entirely missing the point of the exercise.) There's so much movement in this, thanks to his brushstrokes. I know Leyendecker did a lot of advertising work, and I'm assuming that factored into his tendency to use sparse backgrounds. Despite the economy of the background, there's still visual interest thanks to the visible brushstrokes. That carry over lends the piece a feeling of unity and balance, and the high contrast negative spaces really make the figures pop.