In order to keep your piece looking its best, proper placement and regular cleaning are essential. It is essential to keep your artwork away from damp - bathrooms and kitchens are a definite no. Damage from water can usually not be salvaged so this is really important. Display out of direct sunlight as this will cause fading from UV damage. Also consider children and pets when positioning your piece, cats in particular.
Art in frames and domes should not need cleaning, although they are not normally sealed in, I do not reccomend opening them as this can introduce moisture. Don't use water to remove residual dust, this will cause drag from the duster/paintbrush on the piece and damage it. Water will also matte the metal and cause water spots.