What promotion strategies work for your website?

I am a solo developer trying to create something amazing for the world to know. But now, after all the development, I got to know that the most important aspect of creating something is promotion. It's also a part which decides whether your product grows or fades away with time. I have created many products, but I lack the promotion part. Recently I launched my product Frulow here on PH. But, how exactly do I promote it. Just want to know some strategis and platforms you use to promote stuff directly or indirectly. Is it going to take a lot of time.