The Titanic sank in 1912, at the very end of the Edwardian era. This period has been described nostalgically as "a romantic golden age of long summer afternoons and garden parties, basking in a sun that never set on the British Empire."
While this rosy vision was colored by the deprivation of the World War I era which followed, the costume designers for the Titanic films certainly enjoyed dressing their actors in elaborate, romantic gowns, and it is this look that you'll want to emulate for the costume you choose for any Titanic-themed events you plan to attend.
THE EDWARDIAN GOWN
By the end of the period, necklines have moved lower, while waistlines have moved higher. Skirts fall right to the floor, and take a very subtle A-line shape. Lace overlays are widely used, and while daytime dresses would normally include longer sleeves, evening gowns are short sleeve or sleeveless. Visit this link to view the purple dress pictured above on Amazon:
THE EDWARDIAN HAT
The gigantic "Picture Hat" is still in fashion in 1912, lavishly decorated with feathers and silk or velvet trim. It's difficult to find an authentic Edwardian hat today, but the large hat pictured above is a good substitute, especially because it is very light and can be easily pinned to the hair.
THE EDWARDIAN BOOTS
Heeled boots are comfortable and practical, and are always fastened with buttons. Heels themselves are low and wide - perfect for dancing all night! Lighter pumps with low thin heels are also appropriate.
A small beaded purse is a gorgeous accessory for your Titanic outfit, and can be used again and again after your event. In keeping with the elaborate style of the era, both the beading and the clasp should be lavish and complicated.
Women of the era carried parasols to keep the sun from their skin. A very pale complexion was a mark of status, as it indicated that the woman did not work outdoors in any capacity. Vintage fabric parasols are readily available online, in many colors and styles. Choose one with a lace overlay for an extra Edwardian flair.
Evening jewelry was quite extravagant in this era, and would often include sparkling gems in necklaces, earrings, bracelets and even hair ornaments -- all at once! "Subtle" was not a word in these women's vocabulary. Amazon carries several varieties of the iconic Heart of the Ocean necklace featured in the Titanic movie. Try this one on for size!