200 science posts on 100 days (2 posts a day or 1 worthy post one interesting comment a day).
Original title (no copy paste)
Original couple of lines of description (no copy paste)
Should be a topic that interest you and you know about to make a good comment/description.
You should have read the original article (not post blindly).
Make the site lively by commenting, posting, voting...
The quality is more important than the quantity.
Try to select local topics or topics that you personaly know about.