Developers ask a common quest "How to improve the performance of a SQL Query". It is not so easy to answer as lot of factors is related to it. There are some general guidelines that we can follow to improve the overall performance of a query. But I recommended the execution plan to understand the performance of the query. I preferred execution plan when I am building the query block step by step. In this article I am trying to show a basic strategy, how to improve a query by observing the query plan.