If you're thinking of opening up and Etsy shop but not sure where to start, I think the best option is to start with 3D printing because the opportunities are absolutely endless you've got people designing new designs by the absolute tens of thousands each day and for these products that get saturated will become very hard so 3D printing is absolutely a brilliant way to keep listing new products without getting too much competition.

Look at your current competitors bad reviews, this can serve as a great tool in finding on how things can be improved where there's problems and how you can bring the solution in making your platform product or service better.

I sometimes look in advance to what movies will be released in 6 months time, and then base a product around that, sometimes the time you work on a product were the movie has already been released the competition could have beat you to it. Or the movie is not as popular.