I'm going to assume that you don't want a modern legal deck since you have Cloudposts. I would highly recommend you replace the Thespian's Stages with Vesuva and reduce the numbers on the Urza's Lands to a minimum because they are only really good once you have the 3 different ones. Also Sol Ring and some other sort of non land mana-fixing (Myr are also nice). Mishra's Workshop is always nice but I doubt you have $400 to spend on one. Also Mycosynth Golem.