How To Make Money Running A Restaurant?

In addition to what @rosemow has suggested, you can also try the following:

• Ensure that there are optimal and convenient paths to each point of customer and employee interaction (host, waiter station, and table placement).
  
• Place at least 5 fully seated tables or the overall equivalent.
  
• Send your manager to greet every customer and check on every customer.
  
• Don't promote your employees within two days unless they're complaining, and pay for training early.
  
• Always buy at least the Gold advertisement package.
  
• If customers or waiters begin idling, exit to neighborhood view, then re-load the lot - delivery should never take more than two sim hours.
  
• If chefs freeze or waiters begin to idle while waiting for meal creation, exit to neighborhood view, then re-load the lot.
  
• Focus on discount and wealthy customer perks early.
  
• Do not send your household members to engage non-customers while the restaurant is open - if you've done so and the household begins to idle, re-load the lot.
  
• If waiters are failing to remove dirty dishes, send a household member to remove them or the customers will wait for an additional interaction cycle before receiving their food.
  
• If waiters continue failing to remove dishes, reload the lot if one or more waiters is idling persistently.
  

You should be able to achieve five stars and a positive income within the range of 1000 to 3000 simoleons per day within one to two sim weeks depending on failure rates and waiter performance.