First i have to say that you have done pretty well! :3
I really like your drawing just the hip looks a bit off to me so i tried to redline it...
i tried xD
I will add you so you can look and try some things if you want to ^u^
Tipps:
1. don't judge the proportions because the feet and legs have to be a bit bigger for "my" character and i don't have the size change button here *cries*
2. Try to look at human anatomy like: where is the ellbow if i lay it here or there, where does it stop, when it is next to my upper body etc. In your drawing your leg is either too long or, if you wanted it to be more outstreched then the arm would look right up and the pizza and my hand would most likely look in my direction i think (at least if i do the pose). Try not to make the arm longer but maybe the leg closer to the body.
3. Try to imagine what you would see if someone sits like that right in front of you. The left leg will be partially covered and then you can either draw the foot behind the other leg or in the front depends on the pose ^u^
4. Then you have to ask yourself what pose you want (slightly to the viewer or straight to the left in this case) if you combine both it would look a bit weird (my observation). The body of my sketch is slightly turned to us because of the direction of the hip and i think if you lay the ellbow on your knee your body will turn slightly to the left (if your character shall look to the right the i would recommend letting them leaning against a wall or , again, draw his leg closer to the body a bit)
Here is a pose i drew for a character of mine and maybe this one can help you too!
(for all who click on it: Please don't steal/ copy anything please!)
http://sta.sh/0kyedr8pmmz
If you have any questions feel free to message me or write here or on dA
))*