[this2shallPass]

Who is your customer? Why should they use your product over alternatives to solve their problem / improve their life?

This is the realm of product management and product marketing as much as general "marketing".

Read The Mom Test. Follow what it says to do practical user research, so that you can effectively target your niche within time management / productivity tools.

https://www.momtestbook.com/

After that, here's a good video from a YC person about launches, and why you should think of them as things to do over and over as opposed to just once:

https://www.youtube.com/watch?v=3xU050kMbHM