Some extra bling in the shape of shoes, accessories or jewelry! If you need a good tip for bra's for party dresses with unusual cutouts, I sometimes use Freebra in the S-style model (I do however often leave the bra at home completely hehe). S-style works well for smaller breasts, so check out the other styles if you are more busty. They are sold at nelly.
I hope this could provide some inspiration for both outfits and access for NYE. Kisses