One effective method to get new affiliates is to directly advertise affiliates. To be effective, you need advertise where the affiliates are. Obviously, active affiliates are present in the affiliate platforms e.g. clickbank.com, jvzoo.com, click2sell.eu, paykickstart.com, etc.
It all depends... if the offer is digital then clickbank would probably be the best. If you have a hybrid offer (mixture of physical and digital product) then paykickstart would be the best.