I have found a couple of wonderful resources you can use to create a color palette from what inspires you.
The Color Palette Generator
Check out this example of how the Color Palette Generator works on a painting from Toni Swarthout.
Another great options for creating custom color Palettes is Color Hunter.
Both of these sites are easy to use and give you a collection of colors that can use in your creative project.
When you are working with colors how do you decide what colors to use?