Rule 1: The first rule would be to always research! Some features might sound cool, but are impractical. For instance, vibertonez, can only be used on the default songs already on the phone, not on any mp3 ringtones.
Rule 2: Use internet review sites. These give a more detailed description on the phone features. And also raise any problems with the phone that you guaranteed will not see on the manufacturers site!
Rule 3: Try and talk to someone who already has the phone. Play with it yourself to see if you like it.
Rule 4: Search for the best deal! Prices can range a lot, look at the internet, and in store to find the best deal!
Rule 4: Talk to a phone outlet. They can help you find the best deal and raise issues you may not have thought about.
Rule 5: Buy your phone! You'll be happy!