If the only theme at your wedding is a set of colours, make sure you don’t pick too many different ones, or it can become difficult to create a cohesive look. I’m a huge fan of Design Seeds, where Jessica creates several gorgeous colour palettes a week, many of which are perfect sources of inspiration when deciding your colours. There are always six colours picked per photo, but personally I would pick fewer for this purpose.
Jessica has a degree in arts, so if you don’t trust your own eye, maybe pick one of her creations as a starting point? As you can see, she has good taste!