Having fun is what it's all about....!!
Like Richard says, there's heaps of different ways to do the same sort of thing.... Also like Richard I reckon the "variations" way is the easiest and it gives you a preview which is always a bonus.
The other way I like is to select an area, and on a new layer, you fill with the "foreground colour" and then you can play around with "multiply" or different opacities..... also makes it easy to change later on if you don't "flatten" it ....
Cheers
Hewart....