How to get Interview feedback from HR/Hiring manager

Hi folks, so I gave some interviews in past few months but I didn't got any feedback for any of the interviews and when i called HR they kept delaying the same and I gave up reaching out and following up with them. Does anyone have experienced the same and how did you ensure you have a feedback so that you can improve. I am really confused that I am thinking that my interview went good but still I am not able to clear the round and move ahead