I can't remember which preacher said this(I think it's Smith Wigglesworth), "Faith is the currency in the kingdom of God"
Sometimes we want God to show us a miracle so that we can believe. But it's just like going to a shop, wanting to buy a washing machine but don't want to pay! So it's really simple, you want a miracle? then "buy" it with faith. How many miracles we want is really depending on how much faith we have.