Organic sales seo

Hey guys and gals

Ive been selling on amazon since start of january through amazon fba. For the month of january I was using amazon adverts to push my product that i’m currentluy selling. This was a costly process but my plan was to do this to gain sales rank. I spent a fortune I was averaging 10-20 sales per day covering the cost most day of my expences. Come february I turned all ads off to see how my listing would do “organically” without ads. I went pretty quick from around 200 sale rank to now sitting everyday average 700-1000. My sales have went from 10-20 a day to 1-3 a day.

My question is could this be down to a poorly optimised listing? If so is there any guides or tips on how to perform better in amazon search.

On edit the listing does the Keyword section “search terms” does this matter how you use the keywords and is it necessary to use the keywords?

I know thats a long post but I would really appreciate a point in the right direction. Ive googled and its just a ton of people trying to sell you there “guides”