There's a book called 'The Bilingual Family' which I found pretty useful because it doesn't make the mistake of assuming that a bilingual family automatically means OPOL (one parent one language). There are lots of different models, including what you're hoping to achieve.
What I would point out right away is that kids are brutally efficient about language learning - they will learn a language passively or actively if they see a need for it to get them what they want, and they will use the easiest means possible to achieve that. So if you randomly use Irish and then English, and their English is stronger, they will insist on talking top you in English because they know you will understand, so why should they go to the bother of using Irish. You need to create a situation where it is absolutely natural to use the target language, and then you make sure that Irish is the only language used in that particular situation. The ideal thing is if you have grandparents who literally don't speak the majority language, so when you go to stay the DC are forced to use the minority language in order to communicate.
But it could also be a Saturday morning parent and toddler class where everyone sings Irish children's songs together and then goes for a coffee afterwards, talking Irish to communicate all the time. Or the two of you watch an Irish programme together and talk about it in Irish. In our family we had the rule that we only talk English at home, and the community language is for outside the home: it worked so well that the kids are now unable to talk to me in the other language, although they're completely fluent, because only English feels right within the family.
The thing you obviously DON'T do is send your child to an only Irish-speaking boarding school off the coast of Cork for a year in the hope that forced immersion will do the trick, so that child forever associates Irish with unheated bedrooms and being whacked around the head for accidentally speaking English (poor BIL never got over the experience and hated Irish for the rest of his life). That was the 1970s though.