I have product that I launched last year. It did pretty well and started ranking on the first page after a couple months. I based the case study on the following steps:
Setup follow-up email
Product giveaways ( while staying within Amazon TOS )
Early review program
GO HARD on PPC
My Q4 results for the case study product were amazing but I did not pay enough attention to my stock! Right now I have 200 units left at the Amazon FBA warehouse. But I have sold 224 units in January. This means I will be running out of stock in less than 1 month!