Yes, 100% screen brightness will definitely eat up some battery, I keep mine at 60% normally and its plenty bright for me. Running a lot of widgets that constantly pull information also have an impact on battery life. Keeping GPS on is another area that will use a lot of battery. I use location services with Google Now but only use wifi and cell location reporting, only turn on GPS when I need it for more accurate locating such as maps and navigation. Other than that I keep most other stuff on all the time and get good battery life. At the end of my normal 15 to 16 hour day I generally have 60 to 70% battery remaining. I consider myself to be a moderate user, just the normal stuff like calls, texts, email, Internet and sometimes a game here or there.