I paint with 50 shades of grey... no not the novel, but in watercolor!
As surprising as it may sound, most the color we see around us are just different hues of grey. Yes there are some very vivid colors around us, but very few will require you to use straight-out-of-tube paint. If you read my last entry, you know I approach color with warm and cool rather than specific color. Now with that in mind, let's mix a neutral grey. Once we are able to mix a neutral grey, we will be able to move that grey in the spectrum of warm and cool!

First of all, we will use just three primary colors: Red, Yellow and Blue. But we are going to use a dulled down version of them(except blue). So here's my choice of colors:

Red - Burnt Sienna Yellow - Yellow Ocher Blue - Cobalt Blue

If you mix these three colors together, you get a neutral grey. Adding one color more than the other, you shift the balance and the grey become warmer or cooler.

Here is a quick example:

Now if we add Neutral Tint to the mixture, you can now mix darker tones of grey. And with that, you will be able to do a painting like this:

This painting is done with 5 colors (Burnt Sienna, Yellow Ocher, Cobalt Blue, Neutral Tint, Cadmium Red). And to think of it, neutral tint isn't really much of a color, but a darker grey. I use Cadmium Red just for the tail light of the car. So it's really just the 3 colors.

The key is not to overthink about color. Start with fewer colors and add more to your palette as you advance. Pay more attention on your values and shapes. Of course, I do have more colors on my palette. But they are just shortcuts and stronger intensity of the primaries. As always, practice and get familiar until you can mix the color in your mind without thinking! =)