Drupal - What are the various steps to contribute my own module to Drupal.org?

The main pages you need to read are Best practices for creating and maintaining projects and Project application checklist. If you have never done this before, you need to read Creating a sandbox (experimental) project

In short, you need to

• Obtain git access on drupal.org
• Create your sandbox project
• Commit your code
• Submit it for review
• If approved, it will be promoted to be a full project

Keep in mind that your project will likely never be officially reviewed unless you get a review bonus. Participating in other reviews is also a good way to learn about best practices so you can get through the initial review smoothly.