Sometimes friend codes don't give a reward. It is the feature of the game. 
There is a certain amount of luck involved. 
Sometimes you get up to 2 Coins.

To keep out of any bad effect on the game, please change time zones and avoid change the time manually. Also it is better to be done when your game is closed.

Go to "Sociality" (icon with 3 people in the bottom of the screen) -> "Profile". Enter the Nickname and the District name you want.

Please, note that there are several rules for a nickname registration. 
Your nickname is to correspond to the following rules: 
- not to be shorter than three symbols and not longer than 27;
- include at least one letter;
- not to begin with a number;
- include letters from either Latin or Cyrillic alphabet;
- include no spaces at the beginning or at the end;
- include no double spaces.

Buildings can be placed only on cleared areas next to the road. A place that is available for construction is highlighted with green colour. The entrance of the building should be adjacent to the road. Please, mind the surface! There are buildings that  require sand, water and land as a foundation.

Each level-up or your achievement in the game is followed by a pop-up window with an option to Login to Twitter or Facebook.
Press on the relative icon of Twitter or Facebook and an authorization window will pop-up.
Enter your username or e-mail and password to sign in and you will be able to post messages.

You can transfer your game progress through making device backup/restore in iTunes.

Please, follow the link: http://support.apple.com/kb/HT1414?viewlocale=en_US

The gifts are located in the Gifts Shop, not in the Warehouse.

Your main source of income is tourists. When they come to your district for rest and recreation, they pay a certain sum of money for various services. All buildings (except for service ones) make revenue, but up to a certain amount and at different speeds. If you see a dollar icon over a building, that means the building has accumulated enough money to collect it.

By playing the Slot Machine you can earn extra money or presents. You need chips to play the Slot machine, which can be purchased in the store.

Сlick on the Build button at the bottom left corner of the screen and select the "Territoty" Tab. The grass squares are map upgrades which could be used to buy additional space to erect buildings. The arrow on the district image indicates the direction in which the map will expand.

Click on "Services" on the bottom of the screen and select "New Game" in the pop-up window (That will cost you 40 cold coins). Please, note that if you start a new game, your current progress will be lost.

Go to "Social" -> "Services" -> "Gift Code" and enter the code.