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.
Pass time while waiting to regain
After you use up all of your strength and intelligence and are waiting for it to regenerate, there are things you can do to pass the time. One of the best ways to earn a bunch of extra money over time is to hire as many tutors as possible. Since going to the "tutor" section automatically puts tutors who would charge all of the money you currently have, instead go look elsewhere, such as the "battle" section. Go look at other peoples' profiles and hire them from their profile. Try to amass as many tutors as possible. When one gets hired away, you make a profit.
Once one gets hired away, go back to the "news" section and hire them right back. Sometimes, you can end up in a bidding war with another player. If you and the other player keep endlessly buying a tutor back from each other for an indefinite period of time, you can make a ton of money, potentially an unlimited amount of cash depending on how long the other player is willing to keep it going with you.
When you are hiring dormmates, decide whether you want to win fights or to win dances more. Whichever one you choose, load up your dorm with either jocks or nerds. You should be skewed highly towards either intelligence or strength, but not both at the same time. Now go to the battle section and if you have a ton of strength, start getting in fights, and if you have a ton of intelligence, start participating in dance contests. You'll be able to defeat higher level players and earn more money this way. Ignore this tip if you don't care about fights or dances.
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.
Fights and dance offs...