It could be as simple as making certain your calculator has batteries. You cannot get your accounting homework done for tomorrows class if your calculator konks out at midnight. Who wants to head to the local bodega or drug store at the hour?
A game plan for your class or classes is also good preparation.
Commit to study time and block it out on your calendar so that Facebook posts and pizza breaks do not take up all your time. Three hours of self-study for every credit hour is a good rule of thumb. Gak, you say! That much time? Well if you are getting straight A's on less, call me impressed. Most of us are not that brilliant.
Fill our your calendar with key dates and deadlines. Make certain you have read the syllabus for each class and know test dates and assignment deadlines. Review the professor's policies on how assignments are to be handed submitted. It is ugly to learn at 8:00 pm that you really do not have until Midnight on the deadline day and the professor wants that paper submitted by 5:00 pm.
Review each class and develop a study strategy. Is the professor hard to understand? Maybe tape recordings of lectures will be valuable. Is there a disconnection between the professor's lecture and the assigned text? Read the text before class and listen for key words from the text in the professor's lecture. There may be a greater connection than you think.
Even just a bit of preparation when you have time could make the rest of the semester seem like a holiday.