You can use SQL Server Profiler to monitor all the queries against your cube.
With the right options specified, you can filter out most of the events that you don't need.
But, analyzing all the queries and see wich attributes (or other cube items) are affected is quite a tedious task.
Here you can find a video of Chris Webb explaining the SQL Server Profiler in order to design aggregations in your cube:
http://www.microsoft.com/belux/MSDN/nl/chopsticks/default.aspx?id=1499