Two minute drawings are always dificult to comment on. You obviously have a good feeling for the human shape, but my own preference is to aim for a 3D form using the natural light and shade of the human shape. Try a two minute drawing of a part of the model's body. Usually the upper arm, shoulder and neck will give you a variety of shades to work with. There are no edges to a human body, merely places where the surface you are drawing moves out of sight, this is not a line, merely the edge of the shadow.
Actually, not that bad ! :) You start to have a sense of proportion but you need to gain confidance with your line by doing these warm-ups gesture exercises then you might want to spend 1-2h on a longer drawing.
Depends what you goals are too...but I do agree with the upper comment, study how perspective works. "Drawing Perspective: How to See It and How to Apply It" a book that can be found on Amazon for 26 euros.
Well, LucianoSJ, nicest job indeed. Yet, so, I've got one more smaller request made just for you: Why don't you do 5 minutes of 60 seconds, all flipped vertically, if you please, please, please??? And do you know why???? Because, you'll improve your observational talent. And it because, you'll have lots and lots of fun with drawing, particularly your figure studies. Hope it's been extremely and totally essential.