Maeve Higgins's first foray into comedy was in the back of a bus, and Brian O'Connellwas there to see it. Now, she's preparing for her biggest solo gig to date - on her home ground

We're in the bar of the Assembly Rooms in Edinburgh and Maeve Higgins's voice is on its last legs. Not surprising, given that she is in the middle of a marathon 26-gig stint at the Edinburgh Festival Fringe. Last year she had the benefit of doing her routine with her sister in tow - this year, she's on her own and it's proving a tough challenge.

"The venue I was in last time out was pretty ramshackle, and everything was so new because it was my first time," she says. "This year, it's more serious, and I'm in a proper venue with chandeliers. I'm two weeks into my residency, and when I had a day off after the weekend I lost a bit of momentum. I'm back on track now, but my voice is starting to go a bit so I'll be getting to know the mic better."

Higgins has come a long way since cameo appearances on TV and radio first brought her to the attention of Irish audiences a little more than three years ago. This year in Edinburgh, her routine was much slicker, her delivery more confident, due perhaps to her continued success at home. Her quietly unassuming and relaxed conversational style has gone down well, and on Saturday she takes on the Opera House in Cork, her largest solo gig to date.

The gig is being filmed for a live DVD due out in the autumn, yet Higgins is quick to point out that film is not where her ambitions lie. "I guess I did it the wrong way round," she says. "I was only doing stand-up for a few months when the TV stuff happened. It was never my aim to be on television at all. Most people say, 'when are you going to be on television again?' I don't want to be. It's like a comedian here has a joke that goes, 'people always ask me, okay you're a comedian, will you present a game show?' It's ridiculous the way modern stand-up is all about television slots. What's good about this festival is that it is about stand-up. For me it's not about being noticed by some producer, it's about getting better - that's the only reason I came here."

THE BEST PART OF Edinburgh, she says, is taking time out to watch other comedians and broadening her horizons. It's a stark contrast to earlier this year, when she endured a somewhat more torrid time touring parts of Australia. Outside the expat community, she was relatively unknown, and it was the first time in her career that she became acutely aware of the fact that she was a female comic.

"I don't usually think about gender, but touring in Australia was the first time I thought there was a difference between me and the lads," says Higgins. "Sometimes I got on stage there and I would get a vibe like, 'what's this Sheila doing here?' I think they were surprised at my style, which is not at all aggressive. They thought I didn't have any confidence and I couldn't tell if they didn't get me because of my style or because I was a girl. All I could do was hope some of the audience were on my side and keep believing that what I do is good enough. You can't just change style or start doing jokes about rugby. It wouldn't be me."

I recall witnessing her humble beginnings, three-and-a-half years ago on a bus for the last leg of Ray D'Arcy's Go On Be Funny radio competition. Most of the acts were terrible, then a young shop assistant from Cobh took to the front of the bus. It was her first time telling jokes before an audience. She was nervous and didn't know what she was doing there. But her family were on board so she was going to tell us about her sisters, her dad and where she came from, in a self-deprecating, altogether endearing kind of way. There was something about this quirky young voice from Cobh that was original and natural. A few months later, Higgins was offered a slot on the Ray D'Arcy show and her career took off from there.

"That's really strange, you were on the bus - and a bit embarrassing. I heard about the competition and just said I'd try it for the heck of it. I had no long-term ambition to become a comic. Sometimes I ask other performers how they knew they wanted to be comedians and realise how different I was. I had never been at a comedy club or seen stand-up. I think maybe I happened to see some of David O'Doherty's act five years ago in the Project and I took a bit of notice. Having said that, it must have gone into my brain in some way, because now he's one of my favourite comedians."

Higgins says she has no idea where the impulse to be funny came from. "I wouldn't have been in the pub going like, 'hey, hey, your mamma', but my family and I always had a similar sense of humour. You don't think about it at the time but now, looking back, I think my sisters are the funniest people I know. And I know a lot of comics."

Two years ago she went full-time and gave up working in the clothes shop, "mainly because I was getting too busy". Up to that point, Higgins's only other career option was photography, following a stint at Coláiste Dhúlaigh in Dublin. Ireland has been good to her professionally, yet she's keen to emphasise that her recent fame hasn't meant a significant change to her lifestyle.

"Sometimes it's annoying for my sisters when people recognise them. I used to play this character on Naked Camera who was desperate for guys. My sisters would be out in pubs and guys would be like, 'get away from me' or whatever. Really, it's a pretty small price to pay for having such a fab sister as myself."

Higgins is hard at work perfecting her material for her home-ground gig at the Cork Opera House on Saturday. "I'll be doing a different routine to the one I've been doing here, so I'll need a few days' practise beforehand. So it won't be just me on my own with a hairbrush doing it - I'll go to the clubs in Dublin and work out some stuff. The Opera House is a bit nerve wracking; the other big gigs I've done were part of Naked Camera or as charity gigs, when you are on the bill with people like Tommy Fleming. I mean that guy has a huge audience. I need to tailor my comedy more along Tommy Fleming lines I think. Either way, I think I'm ready for it."

Maeve Higgins plays the Cork Opera House on Sat and then tours. Her live DVD will be released in the autumn