If your a minnow your should definitely upvote your own post. You will get a bigger share of the payout, which depends on who votes for you.
If your a whale I think it makes more economic sense not to upvote your own posts, especially not immediately after you post it.
pls what is the difference between Minnows and Whale on steemit. i am new here.
It's just a term which people use to describe how much steem power they have. Small fish are minnows, big fish are the whales.