it depends on what look you're going for. if you want attention drawn to your cleavage, go with a necklace that rests just at the shadow. if you want attention drawn to your face, wear your hair up maybe with little ringlets on the sides with stud earrings or no ringlets and dangly earrings.
if you pick necklace, go with maybe a ring or two, if you go with earrings, a bracelet will balance it better.
Strapless but like is it simple or like what? If your hair is up go just for some dangle earrings if down go for a simple necklace that isn't long. Would be easier if you gave a description of the dress :)