Begin by determining your semester's income or available cash. Your college student budget will be determined primarily by this number. Include parental contributions, student earnings and any other sources of income.
Determine what will be included in your expenses each semester. Will the college student budget include rent, food, school supplies and books, or just personal needs and incidentals? Depending on the student's situation (on-campus or off, for example) and parental contributions (some parents pay all or some of students' housing costs) the budget categories will vary.
Determine the set expenses or bills for the college student budget. These are the categories that remain constant, such as car insurance, tuition payment plan agreements, etc. Include some money each month for an "emergency fund" for unforeseen necessities or emergencies.
Add to the college student budget all variable expenses--entertainment, snacks, incidentals, and other such expense categories.
Balance the college student budget. To make a zero-based budget, make sure that the income exactly matches the budgeted expenses for each month and each semester of college.
Stick to the college student budget, being careful to discipline yourself in your money habits.