My bird hated clickers so that is what I did. Saying "good" should be fine. You can also just click your tongue if you want. Just be sure to have a favorite food reward ready. I used to chop up sunflower seeds to give to mine. Tell us about your bird. Have you had them long?
I have always used a verbal command although I have heard from people about successes with clickers. To be honest, though, I had never heard of clickers until this forum and she was 12 years old by then. Oops!