If they don't ask, and you feel you have been gambling a long time. Simply ask directly "So, what would a person want to do to get a room upgrade?" They might have a specific gambling "point" system, but most often the hosts have huge leeway in giving whatever comps they want to give. Be nice. You are asking for a favor. Hosts, along with every other casino employee, deal with drunken, cranky people all day, many of whom may have just lost their life savings and are quite unhappy.