Effective Clustered Indexes

For effective clustered indexes, follow the few basic points below.

• Narrow – as narrow as possible, in terms of the number of bytes it stores
• Unique – to avoid the need for SQL Server to add a "uniqueifier" to duplicate key values
• Static – ideally, never updated
• Ever-increasing – to avoid fragmentation and improve write performance

For full detailed explaination, read
http://www.simple-talk.com/sql/learn-sql-server/effective-clustered-indexes/?utm_source=simpletalk&utm_medium=email-main&utm_content=EffectiveIndex-20110110&utm_campaign=SQL