SQL Server performance

When having a website which is under performing one of the bottlenecks could be the database.
Several reasons, database schema not correctly configured, too many calls to the database...
Normally I take this approach:
I switch on the SQL Profiler and look at the queries being sent to the database. I mimic online traffic by using tools like JMeter.
From the Profiler one can easily determine queries that take long and tackle those queries by adding any necessary indices, removing any fields that are not used and so on.
Also, I try to group calls to the database to avoid expensive DB trips.
Additionally one can have two connection pools... For Selects one may use a ReadOnly pool. This will perform queries much faster.
This link has some good tips to look at SQL Performance