First, I don't want you to doubt yourself, When i first started off my drawing where-- not the best. It took me a year to improve, It may take longer for others, but i was practicing almost constantly. Watching speed paints and taking photos from real life to help with proportions, perspective, things like that. I suggest looking up people posing and stuff. I'm not experienced in drawing humans at all- So i don't really have any advice there, But I suggest asking someone that can, Like Mush.
I think your drawing are a start, It takes time to get better. Feel free to ask me for more thingy's like this. I hope this helps.