Most Important Factor

Hello you wonderful and amazing people. I do hope you are having a nice start to the week.

I have been working in affiliate marketing for a long time and i know alot of things are trial and error in this industry. However i please kindly wanted to ask what you feel is the most important or most valuable factor in having a successful marketing campaign please? Whether this is doing PPC advertising or baer advertising. I would be forever grateful for any advice or thoughts on this.

Thank...

Most Important Factor