Very few Irish people sound rampantly Irish, so don’t try to overdo it like the man in this video. The best way to sound like a native Irish is to slip in a few potent Irishisms into your speech, playing the role of someone whose Irish accent is waning after a few years in America, rather than playing the Mick fresh off the boat. You’ll also need to learn phrases and the different mannerisms, and not simply the accent. For example, Irish people might say “I’m only just after getting home” where as someone else might say “I just got home”.
You can start off on your path to a great Irish accent with the help of this instructive video.