The first and most important way to prepare for the apocalypse is to be mentally prepared - and to be prepared you must be informed both of what the apocalypse is and what it is not. This post will be focusing on the latter. (Yes, yes, 「まず初めに」, I know.)
When will the end finally arrive, you may ask, and what form will it take? Many have tried to answer this with concrete numbers, dates prophesied by philosophers and scholars and sages and madmen, shocking events gleaned from holy texts or meaningless babble. But what significance do these have, with their extremely tentative links to the physical realm, and their gods who have never once spoken for themselves? I'd sooner believe in global warming than in the Second Coming - the former at least has a few scraps of believable evidence, while the latter runs on faith alone - faith generated by a need for quick answers, for relieving a growing uneasiness in the back of one's mind.
Take the latest apocalypse date, for example - December 21st, 2012. On that date, Earth will crash into the planet Nibiru, the sun will reverse its magnetic poles, otherkin will shed their useless human forms, the Milky Way will achieve galactic alignment, and the 2,000-year ban on magic will be lifted - or at least that is what many would like to believe. Some have begun preparing in similar ways as during the cold war era, stocking enforced shelters with food and water and buying up gas masks and duct tape. There's a (very miniscule) chance that the apocalypse actually will occur on this date, and their preparation will have been worthwhile. But in all likelihood, they're all going to be disappointed when the day arrives, just like people were after the thousands of earlier apocalypse predictions from the Great Disappointment to Y2K. Many will come to the conclusion that no apocalypse will be coming at all, or they will become fixated on a new date, a date that is certainly the right one this time (in fact, there are already a few reports of a new date of the end - May 19, 2013, when solar flares will paralyze the Earth and some malevolent underground organization will reveal itself to the world. I would not be surprised if many of the 2012 believers hopped onto this date as soon as their crushing disappointment faded).
Humans are very comforted by numbers, even when the numbers are wrong. It is easy to assume that someone who says "many people like bananas better than apples" is just making things up, but the one who says "87% of middle-class men prefer bananas to apples" seems to have more authority, even if they did even less research than the first man and simply made up the statistic on the spot. When people feel unsure about something, uneasy, numbers reassure them and tell them what is what - and all of us are uneasy about the future, because subconsciously we know that we don't have much time left. Not only that, but concrete dates are extremely helpful as well - it's much easier to prepare for something two years in the future than something that can happen at any time. The problem with doing this for the apocalypse is that people are deceiving themselves in order to create these deadlines, and they're doing it in such a way that the deceit shatters once the date appears.
Without a concrete date, we're like death row inmates who don't know when we will finally die. Should we live like there's no tomorrow, or as if we will be living for decades more? This uncertainty is extremely disorienting for the human mind. So giving yourself a date to be prepared for is actually a good strategy, but don't be surprised if comets don't start crashing down at that date, or if they begin months earlier than expected.