In the context of aplications based on client-server technology designed for network (Internet), every aspect wich determines performance improving is very important. Due to the large size of the databases, a small change in SQL clauses could determine major gains in the terms execution speed and response time which, aggregated for all users at one time, could produce a smooth working system or one that breaks. This paper presents few tricks for query optimization such as  choosing one SQL clause in spite of another or deciding the right order of clauses for an economic execution. Also, it present indexed views, a new feature of SQL Server 2000, as an effective instrument for fasting applications. Indexed views are an important step ahead in performance optimization especially because of clustered indexes and their automatic management. Automation of indexes and indexed views management brings advantages also by easying the work of designers and programmers, aside of system optimization.