Your figures look flat because you’re drawing what you think it should be rather than what it is.
I would recommend drawing through on the perspective and some practice with making figures out of simple geometric shapes.
Also, I’d consider getting one of those posing mannequins and an anatomy drawing book to give you more examples.
Your poses are somewhat complex from a perspective viewpoint (parts pointing and angles towards different planes). You may want to try some simpler poses like standing with arms down to get the basic proportions right.
Your figures look flat because you’re drawing what you think it should be rather than what it is.
I would recommend drawing through on the perspective and some practice with making figures out of simple geometric shapes.
Also, I’d consider getting one of those posing mannequins and an anatomy drawing book to give you more examples.
Your poses are somewhat complex from a perspective viewpoint (parts pointing and angles towards different planes). You may want to try some simpler poses like standing with arms down to get the basic proportions right.