Very ambitious to start with Harlequins, which are notoriously hard to do well. But your colour scheme is nice and simple and works well. It looks pretty neat as well, no paint going over the lines whre it shouldn't be. I'll echo the oft-quoted advice of thinning your paints- it really does make a difference.
If you want some ways to improve I would do the following:
1. Put some very thinned down grey paint on the white bits that would be in shadow. Under the boob, under the armpit, the back of the leg. Don't overdo it.
2. Get some darker grey and highlight the black bits where the light would fall. The raised bits of the hair, the edges of the coat, the collar and the ribbons, etc.
3. Do a black wash over the metal bits. Once dry pick out the raised bits with the original gold colour.
Hope that helps, enjoy!