This is my sketchbook ! D:

[Prospass]

Hey cool to see you here :)

Cool studies, as always!

Just a quick word on your last character. I think he is falling a little on his side.
Try to find the "balance" line when you're not sure about this. This guy is standing firmly on both feet, so it's quite easy to spot, right in the middle, and try to balance the weight around it.
Also, I think the perspective is a bit off. Always define an horizon, or eye level, and stick to it for the entire image. If you want your character to look strong/imperious like this one you can lower it to the chest/shoulder. =)

Here's a quick paintover, hopefully this will clarify my point ^^




And I second Blewzen, Figure Drawing by Andrew Loomis is an amazing book on this topic =)