If it isn't too late to reply.
My two cents:
What might seem good to you as a vendor might be exactly the opposite to the affiliates.
While giving out high commissions is definitely a plus, do you provide anything more beyond the usual banners and perhaps videos? One of the often overlooked aspect happens to be when vendors/merchants don't provide the much needed text.
If you haven't already, try incorporating seo rich text for product introduction/educative articles with subtle marketing links. In short try to build (useful/relevant)content that you can give away to affiliates that adds value to them and at the same time gives you the much needed push to get the affiliates started to promoting you.