I've been drinking since I was 16, mostly to excess. My parents weren't big drinkers – a glass or two of Asti at Christmas; the odd crème de menthe at their weekly canasta nights – but I took my lead from my schoolfriends. You went to a disco or a party on a Friday or Saturday night, you drank as much as you could, and you failed to get off with girls. You downed whatever you could get your hands on – wine, beer, spirits, mysterious green bottles from the depths of the drinks cabinet – until you threw up. And at the end of the night your mum came to pick you up and you hung out of the car window and spewed some more.

And now here I am, almost 50, and I still haven't tamed the drinking. I can now afford to drink as much as I like, as often as I like – and that's too much, too often. Unless I'm ill, the wine comes out every evening, often after a stiff G&T or two. In company or on my own, at home or away from it, I drink. How much do I drink? Less than a bottle of wine, as a rule, but usually more than half.

Do I need to drink? I don't know. There are moments when I'm not entirely sure why I'm drinking, when it feels a chore: I've started, so I'll finish. But most of the time I actively enjoy it. So I don't want to give up entirely. But for all the predictable reasons – health, bank balance, etc – I would like to drink a lot less.

I'm hoping Georgia Foster can help. She's the hypnotherapist behind the Drink Less Mind, a 21-day programme of emails and MP3s designed to explore why you drink and to help you cut back. Low self-esteem and anxiety are a big part of it, apparently, which may be why Foster is so fiercely nonjudgmental. Her favourite phrase appears to be, "That's OK", followed closely by, "That's fine."

That's an attitude I need more of. We've scheduled a chat before I start the course, and as I'm feeling a little delicate, I spend the morning terrified I won't be able to follow a thing she says. After our conversation, I conclude that this is down to my "inner critic", one of the four weaknesses – oops, no, personality traits – that, according to Foster, push people like me to drink. The others, as I soon discover, are the pleaser (you drink because others want you to), the perfectionist (you take everything to its limits, including drinking) and the inner child (who "loves alcohol" and "doesn't understand the word no").

I think I've got that straight. What with all the trips to the off-licence and the bottle bank, I'm not quite as scrupulous about following the programme as I should be. I do complete day two's personality questionnaire (Do I wake up worrying about what I said or did the night before? Of course I bloody do), but never even start day nine's list of personal, physical, spiritual, emotional and financial goals. Still, as Foster says, "It's not about being perfect." I'm sure she wouldn't even blame me for pausing day 17's MP3 to read an email from the Wine Society.

I do, however, listen to all five hypnotherapy recordings, which tackle such subjects as… well, I'm not entirely sure. Time and again, I stretch out, press play, close my eyes – and fall asleep. This is "absolutely fine", however. As that soothing voice reassures you on day one, "All of the information is still being stored, whether you are in hypnosis or a sleep state."

Many of Foster's clients apparently struggle with their first alcohol-free days. Maybe my daily habit is less ingrained than I thought, or maybe the programme is just the nudge I need, but my two days a week seem a doddle. My only battle with the bottle comes near the start, when I'm cooking, the kitchen starts to smell of garlic and chilli, and I find myself eyeing up the chianti by the stove.

What feels more significant is how my drinking changes on the days when I am allowed to booze. The hangovers don't go away ("Wake up feeling crusty," I note, and, "Wake up feeling rough"), but there's a clear fall in my intake. It's not quite the half the programme aims for, but it's at least a third. Given that my 21 days includes my girlfriend's 40th birthday, and that she's not the sort to let this pass unmarked, this is no small deal. Even on the third day of celebrations, when the pair of us get through two bottles of wine between us before sitting down to dinner, I manage a little restraint. Nothing more passes my lips, apart from a single glass of prosecco and a pint of lager, which I fail to finish. This may not sound much of an achievement – but believe me, it is.

Towards the end of the 21 days, I look back at the diary I've been keeping, just to make sure I've managed to stick to that 5:2 ratio. I haven't. I've screwed up big-time.

Somehow or other, the ratio of boozy to sober days is more like 4:3. That's right. While "wrestling with my demons", I actually forgot to drink.

• Georgia Foster runs the 21 Day Drink Less Mind online alcohol reduction programme at howtodrinkless.com.

How to make it work

• Keep reminding yourself it is just one night and not the rest of your life.

• Find some "AFD buddies" – friends who don't drink or who want to do an alcohol-free day with you.

• Keep busy. Do something you've been putting off, such as cleaning out a wardrobe – or something fun, such as going to see a film that doesn't finish until late.

• If you're out with friends who are drinking, tell them you have a headache or that you have an important meeting the next day. Even better, pretend you have a hangover and can't stomach another drink.

• Each time you think about breaking your AFD, take a deep breath, hold and count for five seconds, then release that breath and hold for five seconds. Repeat three times.

• If you're worried that you won't be able to sleep after an AFD, do some exercise or read a book. The more AFDs you have, the better your sleep will be.