The student population of the University of Idaho is almost half the population of the entire town. Anytime you approach this point, the housing vacancy cycles in the town start to closely follow the ebb and flow of students in and out of the University. This means that May through the start of August are the best times to look for apartments. The later in the summer you get, the fewer apartments seem to be available.
Take the time to have an actual conversation with landlords that you're hoping to rent from. If you're in a hurry and just deal with them via email, you will find it hard to make a personal connection. This plays a large part in the decision that many landlords make, as they want to add a trustworthy, easy to live with person to their rental community.
Many students to commute from town to the University use the Wheatland Express bus service. During the summer months, bicycles are a common method of transportation, and the town is small enough that even new cyclists have no problem traversing it by bike. However, Idaho winters are not conducive to bike riding in the winter, and once the snow flies you'll want either want a car, or to start riding the bus.
The tourist attractions and shopping in the area are all mostly focused at students, as they are the largest economic force in town. For cheap entertainment, many students explore the hiking trails within the nearby national forests. The local bars are mostly filled with students, and places like Mingles and the Corner Club have garnered national attention for being some of the best student bars around.