Well i if you want to get higher i suggest building the muscels in your foot.
By this i mean to do this.
step 1.Stand as straight as possible
step 2.Altrinate between using your feet to make yourself go higher and lowering youself(Raise youself so you are on the flat of the end of the front of your feet.) Hold this for a second then lower yourself so your whole foot is under you and repeat.....do this 10-20 times with out stoping and you should start to feel your self getting tired in that area of your foot.