Okay,
The cream stitching/plunging V-neck means that you can't really wear a necklace at all, so stick to earrings and bracelets for jewellery.
I would keep to cream/gold jewellery-H&M have some lovely cream plastic bead bandles at the moment that are £4.99 for 4, and you could have gold hoops, which will look really summery with your blonde hair.
Cork wedges would look lovely, and help your black dress seem a bit more summery. New Look have some fab ones with patent uppers and a peep-toe. I think they come in a few colours, but their website is not running, so can't check, but sure they were only £15-I'd get the black
The thing with a black dress is that you can't really wear it with bright colours, as it can look very dated (think 80s power-suits), and the black cheapens the bright colour and vice versa.
Instead, you need to add other neutrals, so I would add a raffia/natural coloured bag,
maybe like this one, which does have a bit of coloured detail:
www.monsoon.co.uk/invt/28949311
If I can ever get onto the New Look website, they have a cork clutch too, for £10 I think, which would be perfect.
Love this muted coral bag too, which would work if eventhing else was black/cream/cork:
www.marksandspencer.com/gp/product/B0018APO48/sr=1-24/qid=1214170642/ref=sr_1_24/203-2011775-2600747 ?ie=UTF8&node=&m=A2BO0OYVBKIQJM&keywords=&mnSBrand=core&size=9&rh=n%3A43178030&page=3