Aside from square nails, the oval shape is probably the most classic of the bunch — in other words, you can't go wrong. "It's been on sirens from Tippi Hedren to Jerry Hall to J Lo and Beyoncé," said Miss Pop. This is another shape that looks great on both long and short lengths. To get the look, Miss Pop suggested you "taper your nails gently on the side, then round the tip."