1) Desire for one single thing (in this case money)
2) belief in your ability to get it
3) working like hell according to a set plan and willingness to change the plan
4) maintaining 1) and 2) while doing 3) consistently
However, I still like measurable things, so I still see being rich not as a state of mind but rather as a state of bank account.
Using the word rich for all sorts of other things (usually replacing happiness) seems odd to me. It leads to strange terms like being "financially rich", which sounds as pointlessly overdone as "wet water" to me.