Actually, FunHeart asked me the same thing! What helps is measuring by "heads". Take your fingers and measure the head (up and down). My character is 5 heads high. Draw the head, then measure the head. Take the measure and put them 4 or 5 times below that, and make a mark. On anime characters, the head, chest, and torso measures about 2-3 heads, and the legs are about 3 heads.
I suggest reading the how to anime books by Chris Hart, those really help with proportions. I have had this same problem!