Hi @RDIL and welcome to the forum,
A good place to start would be https://opensource.guide/ - it provides a lot of information on open source stuff.
Aside from that, I'd think a good first step would be to attract users: if your project has more users it is more likely to have more contributors.
You could also try to label issues as good first issue or help wanted, since people generally search for that. Also make sure your repository has a relevant description, relevant topics and a relevent README, CONTRIBUTING_GUIDE and other documents.
Finally, you could try to leverage the power of different coding challenges around. They often allow projects to use a specific label to attract contributors. One I can think of is Hacktoberfest by DigitalOcean + GitHub, but since October isn't exactly near yet, you might want to look out for similar events.
Mark makes some valid points. This is basically a marketing issue: you need to attract attention to your projects, solicit participation, and have the support in place to make it easy for people to come on board.
Write blog articles about individual projects, point to the repo. Publicize those. Project web sites, with use cases, examples, etc. How is your project useful? Why use your project?
Focus. Start with one project you're passionate about, and push it.
Read up on business development, starting a business. Building an open source project isn't much different, except financially.
Hacker News, specifically "show hacker news".
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While not quite the same question I believe its essentially the same as my answer here: https://github.community/t5/Project-Development-Help-and/How-do-we-attract-contributions-to-our-smal...