What elements make this arrangement so aesthetically appealing?
Clothing selection: Natalie Portman's pixieish crop significantly decreases the visual weight of the star's hair. Thus, with her fair-skinned luminosity, the painted linen Prada balances her visual lightness.
Photography: Balance is not all about symmetry. Note how the neckline acts as a frame for the face.
Color: The overall beauty of the composition includes the background (matching the dress and framing the face) and the surrounding print layout (the black enhancing her hair and eyes, the pink bringing out her cheeks and lips).
Rip it off and take it home (not the magazine cover, the artistic concepts):
Visual weight: Choose clothing that harmonizes with your personal presence. Volume, texture, and depth of color all add visual weight.
Balance points: Simply stated, a neckline that is deeper than the face is long is a distraction.
Color: Try a neutral that is the same color value (dark or light), but not the same color, as your skin; accent with colors from your own personal coloring (eye, cheek, hair, or lip color).
Natalie Portman is a work of art, but so are you!