Como dizer "Emperiquitar / Emperequetar" em inglês

"Emperequetar": se arrumar, colocar maquiagem, embelezar-se etc.

To preen.
Usually disapproving: To preen (yourself): to spend a lot of time making yourself look attractive and then admiring your appearance.
Ex.: Will you stop preening yourself in front of the mirror?

To primp
Usually disapproving: To primp: to make yourself look attractive by arranging your hair, putting on make-up, etc.
Ex.: I primped my hair for the date.
Stylists primped the models before they appeared on the runway.

Fontes: http://www.oxfordlearnersdictionaries.com e http://www.thefreedictionary.com

Outras possíveis alternativas: to groom, dress up e doll up.