Just read article explaining SQL Query plans and how to understand them. I find many people don’t know what these plans mean or if they know about their existence they don’t use them.
In the last five or so I showed many people a lot of the basics of this article to them one at a time; and thought about writing it myself but lazy. Anyhow this article is for 2005, so in 2000 you don’t have the XML plan but it gives nice information on how to read and understand this plans to write better SQL Code.
This article is actually from Grant’s book ‘Dissecting SQL Server Execution Plans’; this to buy list for sure.
Ref: http://www.simple-talk.com/sql/performance/execution-plan-basics/