The quality topic is pretty subjective and it's hard to say that, yes this post is a quality one and that is not, excepting spam of course. In regards of strategies to use your SP I really don't see any other better than just your gut feeling and inspiration. Whatever you feel like to upvote at the moment is the best decision.

Should I assign some of the upvotes to people to encourage them to become great authors?

I would definitely do that. I know how hard it was for me at the beginning to get some attention and I was posting four times a day. Pretty long blogs, not like the ones I have now :) I am sure that some newbies that have something to say and not too much attention will appreciate a lot your votes. Other than that I appreciate your intentions and it's great that you are thinking to manually curate instead of simply delegate to bid bots
and get your passive income for your vested Steem. I would do the same.

Great job and good luck!