Below is the list of books and painting video that I find very helpful for developing my painting skill.

Painting Figures
By: Andrea Press
This video shows you step by step on painting miniature from preparation to finishing.

Overhead Lighting 1
By: Accion Press
This book explains overhead lighting technique and how to apply it on figures. Samples are 54mm miniatures but the technique is applicable to smaller scale.

Overhead Lighting 2
By: Accion Press
More on overhead lighting technique and how to apply it on figures. Focus on painting busts. Samples are 54mm miniatures but the technique is applicable to smaller scale.

Black and White
By: Accion Press
This book explains color composition if you want to paint a figure using monotone/duotone color scheme.

Bill Horan's Military Modelling Masterclass
By: Osprey Publishing
Extensive showcase of Bill Horan - a multiple award winning Historical painter. This book also includes instruction on conversion.

Tin military historical miniature of Russia
By: Russian Vityaz
Extensive painted miniature showcase by St. Petersburg Historical painter.