I smoked for almost 20 years (bad I know), but I have now given up.
IMHO, the first thing you need to do is to set a date in the future, a date you will remember but not a BIG day (i.e. not your birthday, New Years Day, Christmas, etc - for the main reason that you will be likely to drink and/or be around other smokers on those days). Picking the ideal date is subjective and is largely down to trying to forecast a day that you *think* will work for you.
An ideal day would be a time when you are not around other smokers but also when you won't be sat around twiddling your thumbs. Obviously I can't tell you when that is as it's something only you will be able to guesstimate depending on your lifestyle/situation. Personally I planned for January 2nd as I wasn't going to be working for a few days (and so wouldn't be around other social smokers during the worst part), I would try not to get plastered on New Years Day (but still be able to enjoy New Years Eve) and I would hopefully be around family who didn't smoke (but not friends who did). For reasons that will become clear I'd recommend you to pick a date around 3-6 months from now.
When you've picked your date you can start to prepare. The first thing you need to do is tell everyone you know, and I mean EVERYONE, that you are giving up smoking on that date. At first people will be like "yeah, whatever", but if you keep gently dropping it into conversations ("only 3 weeks till I give up", etc), you'll hopefully manage to persuade them that you're serious. The reason you are doing this is to create a network of people who expect you to give up (and hopefully even some who expect you to fail) - when you're sat around twiddling your thumbs, debating whether to give into temptation or not, the thought of "public failure" can pull you through. Crucially, you need to challenge anyone who talks negatively about your task (giving up), if they say they've tried to give up X times and it's impossible; tell them you'll succeed. Be determined to prove them wrong, this is peer pressure in reverse.
Secondly; just before your date, go to your GP and get on some sort of 'script. Personally I'd recommend patches because gum and the nicotine tubes create alternatives to the "putting cig to your mouth" habit, imho it's better to break the habit along with the addiction otherwise you'll just be fighting the habit when the nicotine withdrawal has subsided. Most GP surgeries (and some chemists) offer free patch programs, so don't buy them. Not only will you be saving money by joining a program but you'll also be adding more people into to the "peer pressure" pot.
When the date comes you need to be strict. On the night before have your final cig (enjoy it - make it a momentous occasion) and then take any remaining cigs outside and dispose of them so they are unrecoverable (don't just dump the packet in the bin where you can pick them up again in the morning - snap them up and throw them down the bog or throw the packet into a street drain, etc).
First day, wake up and put a patch on instantly. This is where the patches come in handy, they don't stop you craving but at least you know you have "something" (placebo?). Still, it's better than nothing. After breakfast is a good time to do something to take your mind off smoking, do something unusual, not something familiar with smoking (and definitely not drinking - I'd avoid drink completely for, at the very least, a few days). Again it's subjective but maybe you could read, go the cinema, go jogging, walk in the park, etc? Just don't do an activity that you associate with smoking (ie; if your used to sitting playing on an Xbox 360 with a fag in your hand don't do it!). If you're anything like me you'll probably need a distraction after each meal, plan some. Anything that involves physical strain is good because getting to sleep for the first couple of days can be a bitch.
Another important bit; keep accounting (financially) for your cigs after you stop. On your first day go and buy yourself something with the money you've saved, something you enjoy but not something that makes you want to smoke (not a pint of beer!). Maybe chocolate, crisps, etc. Now keep the money aside for 3 days worth of smoking and buy yourself something with 3 days worth of money. Now do the same again for 7 days. And again for 14 days. Again for 30 days. Buy things each time that you want, treat yourself, don't just pay your mobile bill with the money; buy something you've always wanted. It's positive reinforcement.
One final thing I would add is that you should be prepared for cravings for months (long after you've withdrawn from nicotine), especially when you're doing something that you associated with smoking. It doesn't seem like it at the time but you do get over it! Good luck!