[EnderMB]

The best advice I can give to you is that if you're giving a talk on something that you're not an expert on, then tell people you're not an expert.

I gave a talk a year ago about Continuous Delivery, despite being a bog-standard developer that has had to do it on a couple of occasions. I had some general rules that I could carry across from one company to another, so my talk was around these general paths to happiness, and discussing the tools I have used, alongside a generous Q&A.

The questions were all fairly straightforward, and a number of people came up to me at the end to share the same sentiments - they were developers that had been roped into doing sysadmin stuff, and that they found the talk and answers to be very useful.

I have a theory that people often go to talks not to learn something new from an expert on the subject, but for a structured developer chat around an approach on a subject that seems to work for someone in a given context. If they've attended, they're interested in the subject, so as long as what you say is on-subject and clear it's difficult to give a bad talk. From there, it's mostly around delivery, which comes with practice and preparation.