The figures that decide whether a year works, most of which are not tuition.
Cost of attendance is the figure aid is calculated against. It covers tuition and fees, but also books, equipment, housing, food, transport and personal costs. Schools publish theirs, and two schools can differ more in what they include than in what they charge.
Find the published figure for your programme and your living situation rather than the headline one. Living at home and living on campus produce different numbers at the same school.
Equipment, course materials, a deposit, travel, and setting up somewhere to live tend to land together and before any aid disburses. It is a common point of difficulty even for people whose year is otherwise funded.
Ask the school when aid actually reaches you and what the gap is. Many have a process for the gap; it is worth knowing about before you are in it.
Hours worked can affect enrolment status, which can in turn affect aid. Work-study, where it is offered, is treated differently from an outside job.
Before committing to hours, ask the aid office how your enrolment status is defined and what happens to your package if it changes.
Course materials are one of the few lines with real room in them: editions, rentals, library copies and second-hand stock vary the figure substantially, and the required list is usually published before term.
Get the list early and price it yourself rather than taking the bundled estimate.
Send it over. A person reads every message, and if the real answer belongs to your school's aid office we will say so.