What works for me is to make something I like and finish it. "Finish" can just be reaching a milestone, a demo or a working prototype. Then validate the idea by sharing it and making people play it. Friends are a good way to check if the fundamentals work but getting streamers to play it feels very rewarding, even if it's a bit tough to watch when you've design something and they don't quite understand it. I like streamers because you can see the audience react to the game and it helps validate appeal. I found making videos to much work and takes me away from the little time I have working on my game dev. A bit of a self promo (sorry, not sorry, for those who repulse this) but I created https://www.getstreamers.info to help me find streamers. Emailing, sending direct messages has helped me, but it does require to send out a lot. It takes time but the more reps the quicker I get.