Just launched an open-source tool on a few subs; r/SideProject barely moved, but r/software and r/Markdown got like 4k views each. What did something for me was actually just describing the situation that led me to build the thing. People who had the same problem showed up.
It's a great insight for presenting stuff: spend most of the time convincing your audience of a problem and they'll love your solution. Most people expend all their energy on presenting the thing, the features of the thing, the amazing qualities of the thing, etc. instead. It doesn't work. You need to convince people that they have a problem that is solved by the thing. Talk about how expensive and inconvenient that problem is and all the damage it is causing. And then show how existing ways to deal with it are not effective. If you can get somebody to go "hmm, I think I have this exact problem" they are going to be very interested in your solution.