Motion concepts and poses
One thing I almost always try to do when I’m designing a character is to sketch out what I like to call “motion concepts”. These are simple gestural drawings that explore how the character moves and carries themselves. Often these rough drawings can tell you more about the character than a fully rendered concept painting.
Complete the concept
For the final concept I pick a strong pose. Her weapon is so long, I want to give the impression that she’s putting all her weight on her right hip. This will help sell the fact she can hold her exaggerated weapon. I research WWI and WWII military uniforms and develop a muted colour scheme. I want her lightcoloured collar to be her highest area of contrast.