There are lots of hidden options in Windows phone.
Few things which I noticed in Windows phone.
When locked, use the volume up/down keys to adjust music volume without the display needing to light up at all. You can even change tracks if needed by pressing the power button to bring up the lock screen wallpaper - inlaid in this will be music controls and confirmation of what's playing. Having used these controls, the lock screen will disappear on its own in a few seconds or you can just press the power button again.
Exactly how much battery life do I have left?
It's all very well having a little battery icon at the top of the screen, but most of us want a little more granularity than this. Rather than knowing the battery charge is roughly half, it would be helpful to know if it's actually 68% or 34%, for example, i.e. you've got twice (or half) as long left as you might have thought! Head into Settings (I suggest you pin Settings to your home screen as a live tile?) and tap on 'battery saver' - there on the screen (admittedly in a smallish font) is the 'Remaining battery life' in percent. Take the 'Estimated time remaining' with a pinch of salt, mind you - that's the standby time, assuming you don't use the phone much!
Soon Windows 8 phone will be released. I hope the things which keep us annoying in windows phone like message sent notification will be removed.