Color Scheme Design
How often do you see a website where the colour scheme used is really bad? It can really detract from what can otherwise be a great site. Sure, 'content is king' but it doesn't hurt to try to get some of the design elements to work nicely together. On the other hand, I'm sure you will have seen a great looking site where the colours work comfortably together - maybe in such a way that you don't even consciously realise it.
I generally like to be able to justify my design choices - 'the reason I have done this is because...'. I like to do that with colour schemes as well. Often the only design elements I will have to start with on a new site is a logo. If the logo has a dominant colour, I can take that into a colour wheel and see what other colours work well with it. There are different ways to colour match, e.g. using complementary colours. By using a colour wheel to derive a base colour scheme, once again I can provide some justification for my choices.
On very handy online tool is Color Scheme Designer 3.