It's a god first start for your deck, the most important question is what do you want to focus on most? If you want to use tokens then try to add
dragon fodder,
impact tremors and
mardu ascendancy so that you can place a greater emphasis on the token production as far as dealing damage goes. This way you can add
butcher of the horde and use the tokens as demon fodder for its effect as it's attacking. This would work even better if you add
mardu runemark so that your creatures can get stronger AND get first strike.