Fights and dance offs
Fights and dance offs have the same result but require either strength or intelligence. Do an Eavesdrop before starting to learn your chances of winning. Select opponents that have stats similar to yours. If their strength/intelligence ratio are lower than yours, choose them as opponents.
Money
Complete jobs to make money. Although this requires time, do so as much as possible. Hire tutors. If selected correctly, they can significantly increase your stats. They can also earn money. When you hire a tutor, you will pay a fee for their services to get an increase in strength and intelligence. However they can be hired back from you later, and the person that hires them will have to pay more than you did, giving you a profit. The more tutors you have, the more money you can make. Find an opponent to battle that will result with a guaranteed win. Purchase all their tutors to increase the amount of money you can get. Attack them three times in a row for an easy profit.
Stats
When creating a character you will have a choice to focus on strength or intelligence or balancing both of those stats. Create a balanced character by keeping your strength and intelligence at similar values. Start with a dorm mate that gives you the largest increase in strength, then get one with biggest intelligence. They will eventually even out. Always purchase the most expensive dorm mates as soon as they become available. After leveling up your early tutors two or three times, evict them. After getting dorm room #10, get rid of your first six dorm mates and replace them with better ones.