Best selling products vary from region to region. You can analyze the market in your area yourself; there are special tools and services for that. I also sold clothes and shoes a long time ago, but I had an offline store.
You can learn how to sell effectively on Amazon from Darren Campbell, who is the FBA Brand Builder and shares his experience with aspiring entrepreneurs. Check out his YouTube channel.

What do you think is the most profitable product on Amazon today? I've wanted to open my own store for a long time, but I still don't have enough capital to invest in starting a full-fledged store.