SQL Profiler is a specialized tool shipped with SQL server to collect statistics for queries being executed by the application. With SQL Profiler, you can turn the profiler on during business hours and it will determine what SQL queries are being executed by your clients. It will log those queries to a "trace file" that can used by SQL Server's tuning wizard. The tuning wizard will evaluate your existing indexes based upon the statistics collected by SQL Profiler. Then it will recommend a new set of indexes based on your actual client usage.