Schedule as many classes as you can in the first few weeks of semester. This isn't because that's when the lecturers want the students to learn how to use the information resources that the library provides for their resources, but rather so that you can run around totally stressed out, shouting things like "I hate Summon!" at random passers-by. Librarians find public displays of insanity fun.
It's particularly useful in this context if your University Librarian considers that the only reason teaching is busy at the beginning of semester is because you, the librarian, have decided that's when you like to teach, not when the need is. This will make your life much easier, particularly if the powers-that-be have decided that your job is only required to be part-time.
As a part-time librarian, you will be required to do a full-time load of information literacy instruction in your part-time hours. What's awesome in this context is when a public holiday falls during Week 3, so your available preparation hours are further reduced.