One of the areas in which Wicca is different from Witchcraft is in correspondences. Wiccans & Neo-Pagans (not all by far, but probably most) are very ceremonial in their rituals, whether it be for a holiday, spell, or simply to commune with their deities.
Most people associate a color with something....who doesn't associate green with luck, white with purity or red with love?? Using correspondences with your ritual helps to focus your concentration on the task at hand.
So far, I have only a few tables up, but I plan to put up tables for the moons of the year and planets, shortly.
As always, remember that the lists / tables you'll find are only meant to be a guide, you'll have to feel out for yourself how they work for you. Examine the tables and find the correspondences that resonate with you. There are many correspondences listed for each category of intent, use the ones that feel right for you. It is important that you feel the connection between the correspondence and what it is supposed to symbolize - if you don't it won't be as effective.