If you're partitioning solely for performance, don't waste your time.
https://www.simple-talk.com/sql/database-administration/gail-shaws-sql-server-howlers/
If you're partitioning for fast data loads and easier maintenance, then the table's insert patterns and the business rules for archiving/deleting data will be your guide as to what you're partitioning on
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability