Colour Schemes

This is more for designers than developers but some of us have to do both :)

When coming up with a colour scheme for a site or UI it's a good idea to use colours that compliment each other. This isn't just a design thing, it's partly mathematical and there are some sites out there that can calculate compatible colours for you.

This is a good example: http://colorschemedesigner.com/

Another thing that can be useful is the ability to blend two colours together. http://meyerweb.com/eric/tools/color-blend/ allows you to input two hex colour values and it will give you the resulting hex colour value.