You say something and then you realize something even better than what you have just said. You would use “better yet” to introduce what you think is even better than what you have just said. Examples I’ll send you an e-mail about this. Better yet, give me your phone number and I’ll call you this evening to discuss it. We should get feedback from all the employees, better yet, let's call all of them in for a meeting and discuss it in detail.

前一分钟以为要失望，岂料后来的答案更让人喜出望外！

As an example, "I cannot pick you up for the concert using my old car, because it's being repaired. I will have to drive my father's Ferrari". "Better yet".