For fair skin tones like Cara Delevingne's or Jessica Chastain's, self-tanning can be tricky territory. Always be sure to exfoliate, and either wax or shave 24 hours before you apply sunless tanner for the most-even finish. Orange-based formulas, as well as versions that are a little dark, can come off as unnatural, so determine how deep you'd like your tan to be, and go from there. "A good self-tanner will adjust to suit your natural skin tone and pigmentation," says St. Tropez skin finishing expert Sophie Evans, who recommends patch-testing a small area of skin to determine whether or not the product matches your natural tone. The dreaded zebra-stripe effect is also most apparent on pale skin, so use a tanning applicator mitt to ensure the product is evenly distributed. "Zebra stripes are caused by lack of product and overrubbing. When a person is scared of a self-tan, they use a very small amount of product and try to tan a large area," adds Evans. "You can never use too much self-tan as the skin can only absorb a certain amount of tanning agent, but lack of product will normally result in the dreaded streak effect."