Best Practices for dashboards using Query Browser

Hi,

As aligned with business requirement, dashboards are using Query browser to fetch data from universes built on SSAS cubes. The issue here is it takes around a minute to initially load the dashboard which is very long as per requirement. Can I find any document or basic points to be taken care of, on improving performance for these dashboards.There are around 30 Queries being used.(cant integrate the queries to decrease the number). Also , using ranking logics at excel level, does this affect the performance?? (All vlookups and "should not be used" formulaes have been omitted)

Thanks in advance.