If there is a lot of detail on the dress, then definitely skip the necklace.
Go for small, drop earrings. They'll catch the light when you turn your head, but won't compete with the dress. Maybe something like these. Either white or yellow metals depending on what matches your dress.
No need to break the bank... These are just style suggestions. You can find something similar in every price range.
http://www.brilliantearth.com/Tiara-Diamond-Stud-Earrings-Gold-BE3TR1D/
http://www.bluenile.com/halo-drop-diamond-earrings-14k-white-gold_32299
http://www.bluenile.com/pearl-cluster-diamond-drop-earrings-18k-white-gold_35928
http://www.bluenile.com/akoya-pearl-diamond-earrings_8610
http://www.bluenile.com/bezel-diamond-earrings-white-gold_4888
http://www.bluenile.com/asscher-diamond-platinum-earrings_20673
http://www.bluenile.com/vintage-halo-diamond-earrings-14k-white-gold_32348
Also, go for an updo so your hair won't cover up the dress detail, and the small, elegant earrings can be seen.
Have fun...
