The game REQUIRES you to pay attention to money. Period.
In the first week at a minimum, you need to spend most of your time making money.
There are a lot of places to make money.
You can clean your home, work at cafe, work in the science lab (once you have unlocked it by talking to Jimmy) - always delaying compensation until required to take it , use your computer to freelance, and eventually use the boost accounts option on your computer- which is dependent on playing games with Jimmy. Later, when you upgrade your computer you will also have the option to use OnlyCups while female. Ignore the Pleasure House until you have lots of money. Initially, it is a money sink for some time before it starts earning money.
After you survive the first week, you can start to work on other stuff that you need to spend money on.
Banking money once you have a base level (I suggest $100 at a minumum) is another good way to make money. Once you are making at least $25/day from the bank, you only need to work to make the money to buy additional stuff, like supplies (ingredients) at the supermarket, upgrade the computer, buy various sex related stuff.
Sleeping at home instead of the dorms will also save you $5/day.