At 6'x7' you're going to have less space than me so you'll either need to be a lot more creative or you won't be able to accommodate many of these suggestions. One that hasn't been mentioned so far is some ducting to draw fresh air in from outside. Otherwise, in the winter the hot humid air you exhaust out will be replaced by household air that you are paying to heat. Let me also suggest that you buy the largest exhaust fan that you can find. 50 cfm wouldn't make a dent in the humidity in my room, 110cfm still left it extremely hot, it took 300cfm to get the job done.
