Elected officials are strongly affected by the opinions of constituents who are committed enough to a specific concern to arrange a visit.
Some congressional offices are small.
If you are bringing a large group, the office staff may need to prepare an alternative meeting space. Organize a diverse group from your campus' congressional district to attend. Consider what may help persuade your representative. For example, if your member of Congress has a particular religious persuasion, invite prominent community leaders from that faith tradition to accompany you on the visit. You do not have to be a policy expert, but you do have to be well prepared.