I don't think Mastodon has any chance of overtaking Twitter. Here's how I would do it:

Create basically a clone of Twitter, with the same UI and functionality. The goal would be to make transition as seamless as possible. I have no interest in learning about why Mastodon works, why it runs on multiple domains and getting used to its UI. I just want Twitter without Elon.

Make it possible to easily transfer your data, including the people you follow. You would be able to see which of them are on the "new Twitter" and get notified when they switch.

Be inventive in making people convert. Perhaps organize a coordinated switch of many high-profile users to generate a lot of media attention. Or provide incentives such as some sort of ownership share.