I fully agree that the vendor databases are usually less than perfect about naming conventions.

As I work in healthcare in the UK (not sure where other posters are from), we have a nationally provided dictionary of terms and descriptions and we map our fields to those.

It's not always perfect as the term for a field might not be perfectly clear in its content but 30 seconds on Google will usually give you the definition.

I also agree that diagrams are helpful, not only for explaining how tables link together, but we've also found that creating a diagram in SSMS helps when creating SSAS cubes.
We've found that, if you select the FACT table, then clicking the "include linked tables" (or whatever the field is called) also brings all the related DIM tables.