As many as you feel comfortable rolling. ;c)
I garnered the mistaken opinion that reputation was the primary focus of your post - when it was 'earnings on reputation' that you were aiming at.
I quickly learnt that the quantity that one puts out is more of a determining factor of success than quality - that and the number and quality of followers that one accrues over time.
Oh... and self-upvoting. That certainly increases success also - perversely so.
Other factors pale by comparison.
As such one thing that I would suggest is to take another look at those two users that you mentioned - and try to identify the variables at play:
- Their reputation
- Their Steem Power
- Their Number of Followers
- Their Subject Matter (and quality and style) of posts
- Their Commenting Habits (are they following certain users around?)
- Their Curating Habits (likewise)
I suspect that looking at these alone may provide clues as to where you might be going "wrong". :c)
I personally can only speculate as to what you shall find... but I do suspect that the behavioral variables shall set them apart from you in some fashion or other - and you can either emulate or take the higher, poorer, path (as I am doing ;cP).