Locate some good ones. Here's a few:

http://youtube.com/watch?v=I5K5sFl-ydY&search=brand%20new%20live
Brand New - Quiet Things

http://youtube.com/watch?v=a4T458MpG5E&search=elliott%20smith%20live
Elliott Smith - Between The Bars

http://youtube.com/watch?v=l2-LHfBGfZc&search=smashing%20pumpkins%20live
Smashing Pumpkins - Mayonnaise (acoustic)