You need to own over 400sp to qualify. If you have liquid steem or SBD this would be a great time to power it up. Or if you can afford to buy 20 steem. It will also require you to be actively posting so people can upvote your posts if you are accepted as one of the 250.
If you can't pull it off then there will be future months. But personally I'd shoot for the first round if all possible.