Build evidence of research ability. This can include a bachelor's thesis, final-year project, lab skills, coding, statistics, survey design, fieldwork, writing samples, publications, internships, or professional technical work. Supervisors want assistants who can contribute, not only students who need funding.
Be clear about availability. If the project requires lab hours, field visits, data cleaning, weekly meetings, or strict timelines, the supervisor needs confidence that you can commit. Do not overpromise if your coursework schedule is already overloaded.
Ask practical questions before accepting: expected weekly hours, tasks, stipend amount, payment timing, project duration, renewal conditions, supervisor expectations, and whether the assistantship affects tuition or only provides stipend support.