One of the most common defects is the creaking of the hull. Pressing in various places on the body of the phone, especially the volume keys and lock at the ends of the apparatus.
If your phone has a stylus check stylus must be firmly "sit" in the appropriate box and do not fall out when you shake the device.
You should also check the screen of the phone. Turn on the machine, inspect the screen for problem pixels to do it, you may have no special photos with different colors, because you can insert your memory card may not be allowed.
Carefully check the operation of all keys on the keyboard, for example, typing test sms message. All the buttons should respond on the first tap, otherwise there may be problems with the contacts.
Insert the sim card and check the quality of speaker and microphone by simply calling it.
Inspect the contents of the phone, check it with the user manual supplied with the machine, ask to swap the box if it detects the absence of something.
Finally, check all the documents that came with your phone, carefully read the warranty. If you know how to find IME to buy the phone, compare it with the IME on the box.