1. Try diluting both primary and secondary antibodies. 2. Try different blocks like gelatin, BSA, ovalbumin and milk. I use oa combination of BSA, ova and milk. 3. Do all of you antibody steps in block. 4. Shorten up you incubation times. If the affinity of your antibody is strong, it should be all over in 15-30 minutes. Andrey Shaw