While we at work are not "agile" I still find that some of the techniques used are very helpful. Today, I read an article on how to use "Planning Poker" to assign business value to features in a release.

This article's value can be seen if you've ever been in a meeting where 10 new "awesome"/"cool"/"really important" features have been introduced 3 months after the requirements have been completed. To a developer these changes can be frustrating (if we aren't the ones proposing) or exciting (if we propose). Either way leads to either a rejection of the idea or an over commitment of our time.

The best thing taken from this article is the questions to ask of each feature before it is decided to be in the next release. They are:

Original article (AgileSoftwareDevelopment.com), Planning Poker (Wikipedia)