I checked your model out.
You have many duplicate vertices which you can get rid of by going into edit mode and selecting all vertices and pressing W>Delete>Remove Doubles. You can also do the same but press alt+J to convert tris to quads which cut down a decent amount.
I was able to get you from 58,447 vertices with 63,824 faces to 46937 vertices with 52,448 faces.
About 12,000 less vertices and faces.
When doing this it also helps to scale your model up like x3 first, because really close vertices might sometimes count as overlapping and will remove key parts. Then scale back down.
