To get the correct proportions I suggest printing out a 1:1 image of the character. Simply make the shape and check the size with the illustration ;)
My Poppy was 16 cm tall.
FP - flower paste, SP - sugarpaste
After shaping the leg use a skewer (without glue) to make a hole in the leg... If the leg is losing its shape let it dry a bit before inserting the skewer.