Use an earpiece
Part of the radio waves emitted by a mobile handset is absorbed by your body, so it's advisable to put as much distance possible between you and the instrument. In a situation where your phone can't be used in speaker mode, opt for the earpiece alternative - be it wired or wireless.
Text more, talk less
Mobile phones emit far less radiation while sending texts than communicating directly with the other person. And what's more, texting does not require you to hold it close to your brain - where it's likely to do the most damage.
Check the signal
Stuck in a haunted house with fifteen ghosties blocking your path to the nearest doorway? If not, it's probably best to avoid calling anybody in a low-signal situation. Fewer bars mean that the phone must try harder to broadcast its signal, and scientists have conclusively proved that radiation exposure increases dramatically when the cellphone signal is weak.
Hold your phone away
Try to hold your phone away from your body even when you are in the middle of an intense conversation. Why? The smallest distance can effect a major difference in the amount of radiation absorbed by your head and body. Also, refrain from putting the phone in your pocket or clipping it to your belt - believe us, your body can do without the extra radiation.
No tooth fairy
Do not keep your phone in your pocket, or under the pillow while sleeping. Cellphones send out intermittent signals to nearby cell phone towers even when they are not actually in use, exposing you to a lot of otherwise-avoidable radiation.