A college open house is an opportunity to get to mingle with the faculty and other new students. This is an opportunity to make a good first impression with the people you will be spending your college years with. Unlike a graduation, this is not a formal event, so suits and dresses are not required. Typically, these events are considered semi-formal. You shouldn't go dressed up, but you shouldn't show up dressed for a Saturday morning in the yard.
Semi-formal means that you can keep things relaxed, but do not get sloppy. Do not wear jeans. Choose a pant with a flat front and make sure the crease is tidy. You can choose from several colors; black, blue, gray and even khaki. According to "Ask Men: Dress for the Occasion" you should avoid T-shirts. Choose a button-up or a polo shirt. This type of shirt allows you to be comfortable as you mingle with the other guests. Make sure that your shirt is tucked in and that you are wearing either a black or brown belt. The last major part of the ensemble is the shoe. This is not the time to put on your best basketball shoes. Choose a nice dress shoe, preferably in black or brown depending on your choice of pant color.
Women have a couple of options when choosing an outfit for an open house. A dress is uneccessary and is too formal, but a skirt is a great choice. Choose a skirt with a flat front and with a modest length. Avoid bright colors that will draw negative attention to yourself such as yellow, orange and green. Choose an appropriate style of blouse as a top. A button-up is a great look. Your top can be any color you choose and can be exciting and bright. Make sure that you avoid sneakers for shoes. You can wear heels or flats as long as they don't resemble anything you would wear to the gym.
An open house is a chance to mingle and you will most likely spend a lot of time on your feet. It is important to choose the right shoes. Obviously they need to go with your outfit, but they should also provide you a high level of comfort so that you are able to focus on the open house and not on your feet. Avoid wearing accessories such as hats and sunglasses. Women should wear jewelry as long as it is not the focal point of the ensemble.