5000 List View Threshold - Best Practices

I could use a little advice. 

I've just completed a large migration and trying to adjust to Office 365 & SharePoint Online.  One of the areas that my predecesor was fond of, is expanding the LVT to accomodate some pretty questionable designs.  :)

As we've been performing the post-mirgration cleanup, I've been looking for information on best practices as it pertains to folders, indexing, views, archiving schemes, etc...  So far, finding good information on this issue has been pretty frustrating.  

If there is good how-to documentation or instructional videos, please share them!  

Thank you,

Matt