I ran across this infographic recently. It covers some useful tools, though I don't use all seven. Pivot tables however, are a minimum skill requirement for a Lean Business Intelligence practitioner. There are hundreds of resources across the internet for learning pivot tables, including good YouTube videos. With Lean Business Intelligence, you have to be nimble with data; and pivot tables go a long way towards that goal. If you're a Lean Six Sigma practitioner and you don't know pivot tables, you're missing opportunities to understand the story your data can tell.
Here's the lead in to the infographic:
Microsoft Excel is packed with useful data management features that don’t see a lot of use, like pivot tables, index and match, and conditional formatting. If you’re just using excel to sum and chart columns, this graphic can show you some other tools to help you become the spreadsheet ninja you always wanted to be.
The BI side of Lean Business Intelligence covers this topic at a high level.