There are a number of services out there that can help you find CFPs (calls for presentations).

   * https://cfpland.com
   * https://techdailycfp.com
   * https://confs.tech/cfp

I'll warn you it can quickly get overwhelming (at least it is for me) so a few tips:

   * have criteria for conferences (audience, size, location)
   * you can submit a talk without having written it. In fact, it's better if you haven't in some ways because you can tweak it. Just give yourself plenty of time if you do this.
   * you'll be rejected from lots of conferences
   * meetups are usually happy to have you. I wrote about this here: https://www.mooreds.com/wordpress/archives/3418 and this can be a great way to polish talks.
   * think about adjacent talks, so you can re-use components. I have talked a lot about various aspects of OAuth/JWTs and shamelessly reuse portions of them
   * spend some time thinking about how to sell the talk to busy conference attendees. Again, consider the larger context. No one wants to hear about 'how to implement OAuth with <my product>' but 'how to use OAuth to protect your APIs' is more exciting. 'How OAuth saved my bacon and made me a hero' is even better.