How do I get a job lined up a few months in advance?

My boyfriend and I are getting a place together in June. I live in a college town and he is moving here with me. Our apartment requires us to make 3 times the rent (625 a month) which is 1,875 a month, but I work in the college library two days a week, so I don’t make very much and he wants me to only have one job so I can focus on school. That being said, he wants to get two jobs when he moves here, but we need then lined up before June 1st as that is our move in date. So, how do we line up jobs a head of time?