Sabrina Radoncic, 28, Brassy streaks
How she missed: Brassy blonde highlights on long dark brown hair are harsh, especially against a beautiful olive complexion like Sabrina's.
It's a hit! Frédéric cut off more than 18 inches, to Sabrina's delight. The shorter cut resulted in more volume and movement, so that when he added the highlights—lemonade and summer beach blonde around her face, and caramel and cinnamon in the back—they were warmer, more vivid, and more integrated into her new hazelnut base color. He also used different-size highlights to add depth and richness.
The point: Even pretty highlights can look stripey on extremely long, heavy hair. Go for a moderate cut.