Prioritize your class and study schedule. Making it to class and having time to complete your work should be your number one priority in college.
Examine your class schedule and write down the days and times that you are free to work.
Schedule a meeting with your work study boss. Give him your class schedule and a list of the days and times when you are consistently available to work.
Make it clear to your boss that going to class and getting your work done are your number one priorities. This shouldn't be an issue as work study employers are used to working around students' class schedules.
Set a reasonable work study schedule with your employer. Many college students work anywhere from ten to fifteen hours per week while in school. Make sure to leave time in your schedule to study and complete assignments, as well as time for activities and downtime.
Be responsible. Once you've committed to the hours you and your employer have set together, show up on time and always call ahead if you're sick or can't make it to work for some reason.