Stored Procedure bottlenecks.

Hi,
Please excuse my ignorance as i havent been using SQL Server long.
I been put in charge of trying to improve performance of an application that constantly uses many stored procedures for validation and around this is a wrapper stored procedure.
So i would like to try and find if there are any bottle necks by putting in timings for each given validation procedure?
How would i go about doing this?
Any help would be greatly appreciated...
Regards
Wes