I had previously blogged on Missing Indexes and how useful a feature this is for troubleshooting query performance issues. Here is a script for identifying the missing indexes currently on your instance. However, you would definitely need to show prudence in implementing the indexes reported by these DMVs after a due round of testing. You would also need to make sure that nothing else is broken by implementing new indexes.  

 SELECT CONVERT (decimal (28,1), migs.avg_total_user_cost * migs.avg_user_impact * (migs.user_seeks + migs.user_scans)) AS improvement_measure, 'CREATE INDEX missing_index_' + CONVERT (varchar, mig.index_group_handle) + '_' + CONVERT (varchar, mid.index_handle) + ' ON ' + mid.statement + ' (' + ISNULL (mid.equality_columns,'') + CASE WHEN mid.equality_columns IS NOT NULL AND mid.inequality_columns IS NOT NULL THEN ',' ELSE '' END + ISNULL (mid.inequality_columns, '') + ')' + ISNULL (' INCLUDE (' + mid.included_columns + ')', '') AS create_index_statement, migs.*, mid.database_id, object_name(mid.[object_id],mid.database_id) as objectname 

FROM sys.dm_db_missing_index_groups mig 

INNER JOIN sys.dm_db_missing_index_group_stats migs ON migs.group_handle = mig.index_group_handle 

INNER JOIN sys.dm_db_missing_index_details mid ON mig.index_handle = mid.index_handle 

WHERE CONVERT (decimal (28,1), migs.avg_total_user_cost * migs.avg_user_impact * (migs.user_seeks + migs.user_scans)) > 10 

ORDER BY migs.avg_total_user_cost * migs.avg_user_impact * (migs.user_seeks + migs.user_scans) DESC