What kind of products should I promote?
The simple answer is, anything on Amazon! But the big caveat to that is that it must be something that genuinely fills a need of your audience, there's no point trying to sell a dog brush to a goldfish owner.
Now probably the next thing you're thinking is, "Anything? But there are so many categories on Amazon, how could I possibly narrow it down to a single category let alone a single product?"
And to that I'd say that a good place to start is to try and look at the product categories that you already have knowledge or expertise about. The knowledge for that niche could come from one of your hobbies, from your day job or even the things that fascinate you so much that you're up at 3am watching YouTube videos about them.
It can even come from incidental experiences that are not related to your profession or hobbies, for example there may have been a time at work where you helped co-ordinate an office move, or you may have installed security cameras for your home.
Whatever it is, so long as you can get products on Amazon related to that category, you're off to a good start.
The next thing is to step back and think about a goal that is related to your niche and how a product from Amazon might help someone achieve it.
For example, your audience might be people that are running successful businesses, and they may have just gotten successful enough that they're starting to hire staff and lease out office space - this is the why of your audience. In other words, why does your audience need to buy the product you're promoting.
Now that they have office space, they need to fit out their new office with desks, office chairs, monitors, the list goes on - this is the what of your audience. In other words, what will help them address their why.
Now this is the point where you come in, because you can recommend this specific desk, or that specific office chair that is available on Amazon (because you've actually used them of course, and you have a few things to say about them!).
Don't worry if you can't relate to this specific example. Very soon we'll do an exercise that will help you discover a niche that will fit you perfectly!