Colours bring out emotion. They set the whole mood and feel of the photograph.
Here's a bad example! Very bright and dark colours adversely affect the look of skin tone. When colours clash the photo feels unsettling instead of soft and peaceful.
Softer muted colours complement the background, enhance the beauty of the couple, and creates an enchanting feel.
Generally soft neutrals, pastels and earth tones will be your best friend, when it comes to colour.
Things to think about:
What's the colours of the background?
Is it a beach? Then choose colors that will complement the beautiful colors of the ocean and sunset. Neutrals like soft pinks, cream, muted blues, soft greens and white all photograph extremely well, blending effortlessly with the natural elements rather than competing with them.
What Not To Wear:
I have found that black can be a bit harsh on our beaches, as it's a really hash contrast against the white sand. Also very bright or dark colours clash with the soft colours of the sand and sky.
Tip: Try and keep all of the outfits in the same tonal range.
In essence choose colours that will complement both yourself and the background.