Amazon’s RDS supports MS SQL Server Database Engine Tuning Advisor
The Amazon Relational Database Service for SQL Server now supports the Microsoft SQL Server Database Engine Tuning Advisor. The Advisor will help you to select and create an optimal set of indexes, indexed views, and partitions even if you don't have an expert-level understanding of the structure of your database or the internals of SQL Server.
Read more here - http://msdn.microsoft.com/en-us/library/ms173494%28v=sql.105%29.aspx
To learn more about how to use the Tuning Advisor go here - http://docs.amazonwebservices.com/AmazonRDS/latest/UserGuide/Appendix.SQLServer.CommonDBATasks.html