BEFORE YOU START SEARCHING!
This is really important, your postal address on Amazon must match the marketplace that you are in.
This is because Amazon will only show you the listings that will actually ship to the address that you have selected.
Meaning you are only getting a glimpse of the total competition and what the customers will be seeing when they run a search.
If you are searching on Amazon.com in the USA from Australia and your address is your Australian address you will only see the listings that will post to Australia, which is only a small amount of the total listings!
You may also find that you are getting no sales data inside the chrome extension.
Amazon.com (USA) with an Australia postal address = INCORRECT
Amazon.com (USA) with a USA postal address - CORRECT