Being an introvert, how are you doing marketing for your application?

I have built NotionCharty https://notioncharty.com/ and FeedShelf https://feedshelf.com/ applications recently, but I hardly to get paid users for my applications. I do get traffic of 10-20 users per day in each application. I rarely post or tweet about my apps and I don't know what to tweet, that helps in driving the traffic. Can somebody suggest?