Is your display brightness set to 100%? If so, you might try turning it down. I actually have mine set way down to 20% (but I have a dark background, so I can see everything fine). Download a brightness toggle and/or Ctrl Bright for when you need more light on the fly. Brightness management has helped increase my battery life a good deal. You don't necessarily have to go down to 20%, but anything helps.
Still, if you use the display a lot, it will drain the battery much more than playing music, etc (at least in my experience), especially if it's "constantly on."
You can also download a widget "Edit Screen Timeouts" for more refined display times. I have mine set for 1 minute, 20 seconds. I also manually turn off the display with another widget (Lock Screen -- same as pressing the power button lightly) rather than allowing the display to sit even for the 80 seconds when I know I won't be using it for a few mins. Not everyone would want to bother with that, but I've found every little bit helps in this regard.
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