Best way to give away steemit is to identify the people with lowest influence (below 45 influence) and see who sticks to the steemit philosophy best - creates some original content daily (average number of posts per day) and also curates good comments on his/her page. You can assess the quality of content by perusing a few of articles. That is a fair way to distribute steem/sbd to a wider audience. May be avoid people using bots. I am not sure how youll access all people with low ranks but may be select people on random days by looking at new posts. I dont know if such data is readily available though in form of some stats released daily.

Or simply choose people randomly during random time slots and do a giveaway.

Not suggesting a post/article contest since it limits the audience in my opinion.