If you say that a person or room is done up in a particular way, you mean they are dressed or decorated in that way, often a way that is rather ridiculous or extreme. Beatrice, usually done up like the fairy on the Christmas tree
If you do something up, you fasten it. Mari did up the buttons Keep your scarf on, do your coat up
pretty up, make beautiful; wrap up nicely and in a decorative manner; button up, fasten (as buttons)
If you do up an old building, you decorate and repair it so that it is in a better condition. Nicholas has bought a barn in Provence and is spending August doing it up