What are you having trouble with exactly? Is it choosing the colors? Doing the lighting? Everything?
Nice drawing btw!
In the mean time, here are some tips for choosing colors:
Don't use a white background. You want something a little gray. Not too dark but not too light. Having a white background will give you eyestrain and mess with your ability to perceive color correctly.
Separate your colors into different layers, one layer for each color. This allows you to do the following:
> Pick colors close enough to what you want but not perfect. They're just placeholders at this point.
> Use a colorize tool to adjust each layer until you have something more cohesive. Having each color be on its own layer will allow you to freely adjust the layer without messing up other colors.
To help you identify which colors need adjusting, try zooming out of your drawing and don't focus on any particular part. Maybe squint a bit to make your eyesight blurry. Do any of the areas look particularly dull or too vibrant? Do some of the colors clash with other nearby colors or stand out too much? Grab that color and tweak it!
Splitting your colors into layers can also help you experiment. You might try a red jacket at first, but after playing around with color sliders, you decide that a green jacket looks better.
Hope that helps and feel free to ask for specifics!
