Do you have apps open? To turn the off double click the home button and hold down the application on the bottom bar for a few seconds. Once they start to wiggle hit the little red circle until they are all closed. Also turn off the wifi if you are not using it.
If you run multiple apps, play music/videos or do anything else like this, this can reduce your battery,Normally a 2 hour battery is not normal I would take it to apple and have the give you a new battery