Last year I was talking to a friend about a problem we had and decided to build a tool for it. He would do the marketing and i would do the coding, but he decided to leave right before the app is ready. Now i dont know how to market or even where to start. I know that i need to post the app on Product Hunt but that's it, i don't how to make an ad campaign plan or things like that. It's in smallish niche and that makes it even harder. So, should i try to find a new marketing co founder / partner ( if yes maybe some tips will help on how to find him/her ) or do the marketing myself? Also the app can be extended to have a lot of different functionalities, what's a good way to test what are more in demand?