Windows 7 Phone is pretty cool. The tile based look and feel is very different from the it's competitors. Unfortunately some of the most useful features are hard to find or completely missing. Here are some of the ones I looked for when I first got my hands on a Windows 7 Phone.
Unfortunatly, this feature does not appear to come built-in. After searching, I have come to the conclusion that there is no simple solution like the ones available on Android and iPhones. If your technically inclined, there are a few options but nothing I would ever want to unleash on the typical user.
Silence a call
Simply press the power button. The phone will go silent but the caller will simply think that you're away from the phone.
Why Microsoft made this useful feature that turns off all communications when flying or in hospitals is beyond me. At least you'll find this one in Settings, right between Theme and Wi-Fi. Unfortunately you can't pin this to your Start screen but you can pin Settings.
Remaining Battery Life
Having a little battery icon at the top of the screen can be useful but when you need to know whether you've got 20% or 10% battery reserves available, it's of very little use. Head back into Settings again (did you pin it yet?) and tap on Battery Saver. You'll find the Remaining battery life listed under Battery info in tiny font at the bottom of the list.
Microsoft, you're making us work harder. Please think smarter!