with me, it depends on both the look i am going for, and the pigment i a using. if i plan on putting a shadow on top, then i'll use a mixing medium with the pigment, since it helps the shadow adhere, i've found. there are certain colors, also, that i find really work well wet, such as melon, fuschia, rebel rock blue, and kelly green. others, such as grape and emerald green, i prefer dry. plus, i like using the lighter, highlight colors dry, with a fluffy brush, such as the 217.