I would like to see you draw some things you see every day, because now that you started your sketchbook I can see some thing are out of shape a little. Not something to worry about, but something to work on, and man made things are easier for a good start, and what you know best you should be able to draw better. Let me know when you have something so I can take a look. No hurry, it is best if you take your time.
Hey thanks for the encouragement in my sketchbook!
That first drawing of the chest looks pretty good but I think you would really benefit by drawing the whole figure. It look like you tend to shy away from the feet, and practicing drawing the whole body will help you figure out proportions and how each part of the body relates to itself. Keep posting!