Create your menu.
Like any top-notch eatery, the most important part of your restaurant is the food. Food is divided up into four categories: Starters, Main, Desserts and Drinks (unlocked at level 15), and you'll be able to eventually serve up to three different dishes for each course. Each dish you can create in Restaurant City is composed of three or four different ingredients -- you'll need a set of those ingredients every time you want to level up the dish (up to level 10). The higher level your dishes are, the higher your restaurant rating will reach.
Ingredients can be obtained in multiple ways. Every day, three random ingredients will be available for purchase with Coins from the Market. You can earn a random ingredient by correctly answering the Food Quiz every day (found in your mailbox). You can also plant seeds to grow herb ingredients like Oregano, Bayleaf and Basil in the garden. In addition, you'll receive one free ingredient the first time you visit a friend's restaurant. If you're desperate to create or level up a particular dish, you can purchase individual ingredients using Playfish cash.
Trade with friends.
Since most of the ingredients you receive in the game are randomly selected (with the exception of purchasing them individually with Playfish cash), it's good to know that you can look to your friends to find that last piece of your dish. When you visit a friend's restaurant, you'll be able to see which ingredients they currently have and make an offer to swap with one of yours. Your friend can approve or reject the trade request when they log in (chances are they'll approve unless they're also working on dishes that require that particular ingredient).
Hire your friends to work!
You'll be able to hire more friends as either chefs, waiters or janitors as you level up, and unlike with trading ingredients, your friends don't need to be playing Restaurant City in order for them to work at your joint. However, since their happiness decreases over time, you will need to tell them to rest every once in a while (free, but you'll be temporarily short a worker) or give them food (which costs money) so that they'll continue to work.
Design your restaurant.
Restaurant City will start you off with a few tables and chairs when you first open your place, but after that, it's up to you to add more seating/serving areas, as well as stoves for chefs to prepare food at. As your restaurant's rating goes up and more customers come in, you'll probably need to optimize the arrangement of tables and chairs around a stove in order to maximize your employees' efficiency. Usually the best way to do this is to create 'islands' -- groupings where one or two stoves can provide food to six or seven tables, with one waiter 'stranded' in the center to serve the customers.
As you earn more expendable cash, you'll also be able to customize both the interior and exterior of your restaurant with new flooring, wallpaper, decorations and more.
Check out More on Restaurant City or Play Restaurant City.