Waits and queues can be used to identify performance improvement areas within SQL Server. Wait events indicate where SQL Server is spending time waiting instead of servicing a request. When a request is waiting, the response time experience of a user is affected directly. The longest wait events highlight the most important or relevant queues (that is, Performance Monitor counters and other data). The wait event information can be extracted easily from the Performance Dashboard.
To learn more about the methodology and each of the wait events, see http://www.microsoft.com/technet/prodtechnol/sql/bestpractice/performance_tuning_waits_queues.mspx.