Typically restarting an Android cell phone should get it out of the Safe Mode feature (a battery pull too as it is essentially a soft reset).
If your phone is STUCK in Safe Mode though and restarting it or pulling the battery doesn’t seem to help at all then it could be a hardware issue like a problematic volume key. Mike T. was on the right path here because if the Volume + key is having issues and you press it when booting up your phone you can be loosening it up or in a way show the phone that you are not TRYING to enter Safe Mode intentionally by pressing the Key combination to do so.
So check those physical keys too, it might just be the fix you were looking for. You can read more about this trick and some other tricks that might help at [http://www.smartmobilephonesolutions.com/content/how-to-get-android-phone-out-of-safe-mode|How to fix an Android stuck in Safe Mode]. Usually the terrific advice already posted on this page should get your phone out of Safe Mode but if not then one of the tips on that page should definitely help.