Pretty good. I used to draw some myself, but that was a long time ago. I did pencil sketches in high school, charcoal pencil and conte crayon in college.
Your outlining is pretty heavy, though if you intend your picture to be a simple cartoon, that's fine. If you wish to give a more realistic image, use shading techniques (shape and shadow) to define edges and texture, and lighten up on the outlining.
Your perspective is correct, as it's clear in the bottom drawing the girl is in a hallway. But the object around her feet is confusing; to me it looks like some type of piping, but I'm not sure if that's what you meant by it. If it is, it doesn't seem to line up with the perspective of the hallway. When I used to draw, I would try to ask myself "If I were looking at this for the first time, would I recognize it; would it make sense?" Sometimes, since we are doing the drawing, we assume the viewer will see what we see. (Of course, if you want to be another Picasso, it doesn't matter if the drawing is recognizable!) Are these drawings totally from imagination, or did you use something to guide you, as a photo, or another drawing from a different angle?
Snakechic was right about keeping a paper under your hand, it will keep you from smudging your image. But still don't lean and drag with your drawing hand, even with the paper underneath. It's best to use an artist's easel or a drafting table to draw on, the angle helps keep your hand off of the drawing in the first place.
Some exercises:
Practice your circles and ovals, as these tend to be shapes that are often misdrawn. My instructor used to call these mistakes "footballs and corndogs". Just practice by drawing objects that are round. This ties in with perspective; once I turned in a paper where I threw a bunch of objects (tin cans, thread spools, buttons, clock springs, coins) onto a checkerboard, thus trying to show my knowledge of the perspective of both lines and circlular shapes. It must have been pretty good, as he used my drawing in a slide presentation to classes.
Try drawing an object from a different viewpoint, as in don't draw the object, draw the area around the object. Example: if you were drawing a wooden table chair, don't draw the legs, seat, or support struts; draw the space between the leg supports, and between the slats on the back.
Another way of drawing an object differently: blacken some paper totally and evenly with a charcoal pencil. Then use an eraser to erase your picture out of the dark background. You're doing the opposite of what you normally do to create your drawing, and this does help with learning your shading and shadows. Just make sure you use the hint about keeping a paper under your hand!
Try a continuous contour drawing. Pick an object to draw, and once your pencil hits the paper, do not pick it back up until the drawing is finished. You can cross over lines, and retrace over a previously drawn line if needed.
Hatchline drawing: Once your basic outline is lightly sketched, you will use shading to fill out and form your picture, by short, light, strokes made in the same direction. Remember when you were a kid with a coloring book, and you just scribbled every which way with the crayon to fill in an area? Think the opposite. You will only go, say, in an up and down, steady, smooth movement to shade in an area. If you need it darker, you still use the same pencil movement, just go over the area again. You don't use pressure to get it darker, you are just placing another layer onto the first. It's important for all of your strokes to blend together; you don't want to see individual lines.
Interesting fact: My instructor once asked us what we thought was the hardest part of the human body to draw. We were all suggesting the eye, face, and some other...er...more detailed areas. The class figured that the hardest part to draw would be a rather complex area, requiring more lines to make it. Wrong. It's the human back, because it's designed simply, without too much breaking up of the area. Complex areas are actually easier to draw because you have a lot of reference points to compare each other with. A back? Maybe shoulder blades and ribs, though if you have a heavy subject, these may not be noticable at all. So you have to use the shading of muscles, and maybe the shoulder blades, to give any shape to the back, or else it will look like a big blimp. (I wasn't too bad at figure drawing either--though I never could tell my parents that I was drawing nudes. 
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Practice, practice, practice. Draw anything and everything. Wad up a paper bag, throw it on the table, and draw it. Draw all sorts of objects just laying around the house; rubber bands, nuts and bolts, a ring of keys, a glass of water, the dog's bowl full of Kibbles and Bits, a plate of spaghetti, your sister's inside-out socks laying on the floor. Open up the medicine cabinet and draw the contents as it is. Prepare a bubble bath, try drawing all the foamy bubbles. As Snakechic said, have fun!
