Tennis star Serena Williams is training to be a nail tech, and one of the things she's learned is to tip manicurists more!

"I didn't realize they do so much work! There's actually an art to it," she tells People magazine. Williams, who is working on her certification in Florida, adds, "When I was younger, my room as a nail salon. It had every color you could imagine on the wall."

Her favorite products include Birchwood Sticks from Sephora and CND Speedy Top Coat. For polish, she likes "fun and bold" red (Sally Hansen Diamond Strength No Chip Nail Color in Diamonds and Rubies); leopard print Minx nail coverings, which she wore at the Australian open; a "cool neutral" pink for the spring (Essie Nail Polish in Mini How High); and  "bright and happy" yellow for the summer (ORLY Nail Lacquer in Hook Up).