Businesses
At about level five you will have to repeat a cycle of keep yourself alive while earning resources. However when you unlock the business jobs, you can earn resources overtime. Any job that has a small clock next to it is a gradual job. After you are paid the initial salary, each time you take a turn you will earn a certain amount of money or junk. Use such jobs to get paid over time.
Leveling
When first starting, your actions will be limited. Focus on rummaging through trash to get junk and a small amount of experience points. Do this repeatedly while keeping your other stats up in order to level up. As you level you can purchase better options for each of your character's house, education, and transportation categories. Know what the requirements are for those upgrades. Some upgrades are purchased with junk, while others require money.
Resource conversion
Resources can be converted into the other types of currency. You can turn junk into cash, cash into gold, and gold into cash.