Have you ever read the signature campaign guide?
If you don't or perhaps have forgotten, let's look at it again:
Signature Campaign Guidelines (read this before starting or joining a campaign)I think the above hand campaign guidelines are enough to give managers insight into how to run their campaigns well.
One of the important points is in the quote below:
Do not just automatically accept any user that signs up to your campaign. Check their posts first. If they're all short sentences or unsubstantial or in very poor English then they're likely not going to change their habits. If every campaign only accepts and pays for users who have made fairly constructive posts then this will instantly clean up the forum as any poor posters will have to improve if they want to earn anything from a campaign.