What battery life are you guys getting? Mine lasts for only about 10 hours. (Use 3G occasionally)
Disable NFC (does it have it?) and location. Browsing eats up battery, but not any more than I have seen in other phones. Its got a rating comparable to the 920 and mine lasts a full day with decently heavy screen use and wifi on all the time.
Nokia Lumia 520 goes through our extended battery testing regime, see how it managed - GSMArena Blog
Is it new? If yes allow for a week's use for the battery meter to calibrate. Mine improved dramatically within a week of purchase and I have other reasons to believe that its the battery calibration that causes this rather than an actually drained battery. For example -try to switch on the phone about 10 minutes after it shuts down of low battery and you'll generally find that the phone powers up and reports anywhere from 10-30% battery left and actually goes the corresponding distance. Would be worth trying