It's a matter of either investing in the system (fiat currency and/or converting other crypto in the market game to STEEM), creating great content that is popularly upvoted, or both.
Personally I am a bit disturbed someone so smart and with much power here uses his voting power to profit himself so much. Yet I can't complain, his content is excellent and he is free to promote you or me or himself as he sees fit. But this "upvoting self" is really hurting the community as a whole. For all the Whales upvoting their own content and comments (and there are a LOT of them) it is only depleting the rewards pool for those of us off to a new start here. I would like to see that $40 upvote go to someone like you (should you be posting original content that's good).
You can find many articles detailing the harm to our community as a whole due to people self-upvoting (Whales in particular, since they wield the most power here) with a simple search.
Hive account@l0k1 is currently creating a bot project Hive account@smackdown.kitty that is designed for "Busting the Bubble of Self-voting". And I choose to support it 100%.
Don't get me wrong, I do not wish to attack Hive account@craig-grant. Just wishing to answer your question and explain how potentially harmful such actions can be to the rest of the community. I will definately keep following craig-grant and upvoting for him whenever I have voting power to spare (BUT Red Fish and Minnows will come first).