How to get skinny legs as fast as possible ?

If i walk 30 minutes everyday of the week, that i do 2 hours a week of sports at school, 1 hour of cardio a week and horseback riding once a week, can i get skinny legs fast =S ?
I eat healthy and drink a lot of water.

Is there another effective way to get skinny legs fast ?
Thanks !
Ps : I walk/jog on the treadmill ;P