See the website of the Dormitory Desk, Student Affairs Section of Waseda University.
Waseda University recommends the following agencies:
The Student Affairs Section of the Student Affairs Division can help you find part-time employment. For more details, see MyWaseda (a portal site you can use once you are admitted). Applications for part-time work with limited openings or on-campus work such as proctoring exams can be submitted in person at the Student Affairs Section.
There are about 500 university-certified clubs for academic pursuits, arts, sports, and other activities. Including clubs that are not certified by the university, there are approximately 2000 clubs on campus. Students have ample opportunities to interact with other Waseda students through various club activities.