What's the best way to talk about why you were fired from your last job in an interview?

So I've been looking for work for a few months now and while I've been able to secure some interviews, I'm constantly getting shot down for the job and I can't help but feel like it's because I was fired from my last job. It was an office job and I was fired for not paying attention to the quality of some of my work and not being focused on details in general. I try to explain in interviews that I learned from the experience and that I left on good terms and would try not to make the same mistakes again but I don't feel like I sound convincing enough and I just generally get nervous whenever the topic inevitably gets brought up. Any advice or tips on how I can talk about this in a better way?

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