Designated Driver

Let's face it: being designated driver doesn't just mean driving everyone home. It also carries with it the implied responsibility for everyone's well-being. Anything goes wrong, and it's you that's left carrying the can. The best way to deal with this is to be frightfully scoutish and "be prepared". So anticipate and plan for the worst, and take the steps you can ... or take the bus.

First, know where you're going to park before you leave. Make sure that it's somewhere even a blind alien could find. And, declare to your charges what time you and the car will be leaving for home, impressing upon them that this is not an estimate, but a fact. Actually, it might be an idea to advertise the time slightly differently (tell them to be back at the car an hour before you really intend to leave to allow for stragglers). Secondly, provide sick bags - much easier to deal with than reupholstering, not to mention cheaper

Body Protection

First, know where you're going to park before you leave. Make sure that it's somewhere even a blind alien could find. And, declare to your charges what time you and the car will be leaving for home, impressing upon them that this is not an estimate, but a fact. Actually, it might be an idea to advertise the time slightly differently (tell them to be back at the car an hour before you really intend to leave to allow for stragglers). Secondly, provide sick bags - much easier to deal with than reupholstering, not to mention cheaper

Drunk people don't feel the cold (remember?) and are oblivious to blizzards. You're not, so wear clothing that will keep you warm. Feeling cold does not improve anyone's sense of humour, but staying warm might just lengthen your tether a wee bit.

Blackmail Protection

One of the pleasures of being sober while all around are inebriated is that you remember vividly all the amusing and embarrassing escapades, and can blackmail the guilty parties afterwards. Why stop with mere remembering - what's wrong with a little celluloid evidence?! Take a fun camera, though, not the Rolei, just in case of disaster.

Refreshments

Cola and Orange Juice can get a bit, well, dull after too long, quite apart from what they do to your digestive system. Try bottled water with a touch of cordial, take a flask of coffee, or maybe bovril or soup.

Persuade your passengers to frequent bars that have heard of coffee and tea, in fact make it a condition of being designated driver. Experiment with alcohol-free cocktails, mix your drinks with impunity. Rediscover the joys of midget gems, fruit pastilles and the like, and have one instead of a nip to celebrate (you could even splash out on some exotic chocolates -- they're not going to melt in our Arctic conditions). Chocolate-covered coffee beans are great for reviving flagging energy reserves. Chewing gum might help stop you biting someone's head off.

Communication

If you all have them, make sure everyone carries pagers or mobile phones (and you should have the numbers). Contact everyone about an hour before you leave to remind them, unless of course you are lucky enough not to have been split up.

Disaster

Know where the first aid stations are, and the hospitals (Edinburgh map here). Also, just in case, have emergency contact details for everyone in your party; and either a mobile phone or plenty of change with you. When it all gets too much... sometimes it does ... stick your Walkman on (that you prepared earlier) and lose yourself in your favourite music for a while...

Forgotten Address

It might sound daft, but know everyone's address - they might have forgotten it by the end of the night! Also, work out in advance the fastest route that allows everyone to be dropped off, rather than prolonging the agony.