Strobing is all about layering products and perfect placement. Romero recommends piling on three different levels of illuminator. Start with a cream highlighter like MAC Cream Color Base in Pearl ($22). A balm formula is easier to control than powder. Look for a product with shimmering particles and a light-reflecting finish.
To get the perfect placement, stand under a bright light and look into a mirror. Notice all of the places that the light catches on your face, such as your cheekbones and nose. That is where your highlighter should go.
On your cheeks, the illuminator should be strongest on the apples and taper out near the tear ducts (similar to a teardrop shape). You can also accentuate the brow by adding a thin layer of shimmer just over the tail of your arches.