Right - you've got the right attitude which is 'I start from today'. I'm assuming you're not planning to drink on New Year's Eve but just crack on from right here? You will have to get used to celebrating without booze, so no time like the present. You'll also have to get used to being around other people when they're drinking.
The book that really helped me is this one. Available for download so if you like the look of it you can read it today.
You don't have to say, but if you add up your units do you think you are drinking at unsafe levels? A trip to your GP might be a good idea to see if it warrants running any blood tests to check to see if you need to boost anything to help your liver recover - I mentioned on a recent thread I had to take folic acid when I first stopped drinking but I was in such a poorly way that I have no idea why now. The other purpose of telling your GP is to make this real. If you're planning to quit for a year, you'll need to tell people you're doing it - even if you say it's a health goal rather than concern about your inability to stop drinking once you start. Most people will understand, some people are likely to be stupid (normally because they are equally sure their own drinking has reached unacceptable levels).
As you are an irregular drinker you may not have to watch for your triggers in the same way as those of us who drank daily or nearly daily, because alcohol was part of our day-to-day routine whereas for you it sounds like it's more in social situations? You will need to plan carefully for how to get through these, being aware that initially it might be easier to not attend some of them than put yourself through the mill each time.
You may need to find some distractions if you think you might drink in the evenings; exercise or computer games or crafting of some kind, whatever it takes to keep your hands busy.
The main thing really, though, is to go public with the decision. Much harder to back down if you've made it public. Posting here is a great first step.