There is a bit of different opinion here, but in general up voting your own posts is fine. As people get to higher levels of Steem power, you will see that some also upvote all their comments, as well as their posts. Like all things, there's a point at which it is fine and a point at which it becomes grotesque. For me, I upvote all of my blog posts but none of my comments. That's my line, but I have friends that I respect who upvote certain high profile comments. You just have to follow those you respect and follow their guidelines. We all have our own paths, n'est pas?