I'm also applying to CA for Fall 2013! Like Katie, I also attended PreCollege (HI KATIE I MISS YOU) and loved every single second of it. Not to put words in her mouth, but something we learned in figure drawing classes was to emphasize the action of whoever you're drawing- verbs, not nouns. Your portfolio as is stands now is great, but many of the figures are standing still or sitting- not very dynamic poses. A fun exercise is to take an action (for example, swinging a baseball bat), break it down into key poses, and sketch each key point in the action. It's more fun than it sounds! Best of luck to you as you prepare your portfolio :)