Enhance SSRS 2008 R2 report performance

Hi, We are using SQL Server 2008 R2. I am looking at different options that would enhance performance of the report when run in BIDS environment or ReportServer. I usually call a stored procedure andmost of the time these stored procedures take less than 10 secs to retrieve results in SSMS but take over 5 mins from the ReportServer. What areas should we look at?

SQL Server Version: Microsoft SQL Server 2008 R2 (RTM) - 10.50.1617.0 (X64)  Enterprise Edition (64-bit) (Service Pack 1) (Hypervisor)

Thanks in advance..............