The following suggestions should be at the top of your list when preparing for an emergency. In fact, it would be even better if you would take care of these things BEFORE the threat of an emergency!
If disaster is imminent (and even if it's not), stock up on water! Water is necessary for drinking, cleaning, bathing, sanitation, making food, etc. Purchase cases of bottled water and fill up every water container you have because you can never have enough water when the grid is down. Empty soda bottles make great water containers for drinking, while empty laundry detergent containers rinsed and filled with water are great for water used for cleaning and sanitation.
While it would be best if you already had a 3-month supply of rotatable goods and a year supply of longer-term food storage, many do not. If you're one of those people and you're lucky enough to have ample warning of an impeding state of emergency, purchase foods that are shelf-stable and easy to prepare. Canned goods and boxed meals will help get you through a short-term emergency.
Why ice, you ask? Because if your fridge and freezer aren't completely empty, you're going to wish you had some ice on hand to help keep everything cold until you can eat it. In an emergency where the grid is down, you'll want to eat your refrigerated and frozen foods first. Then start on the non-perishable foods. One of the easiest things you can do to make sure you have ice, is rinse and fill up old milk jugs with water and freeze them. And once they melt, you can use the water inside!
Never let your gas tank get below half full. NEVER! You never know when you'll need to evacuate or get home during an emergency. Either way, you could be stuck on the road for hours, or gas stations may run out or lose the capability to pump gasoline. Always leave your tank closer to full than closer to empty. It wouldn't hurt to fill up a few gas cans, too, for good measure.
If you don't have one, get one! You should have AT LEAST one emergency kit in your home, at work and in your car. It doesn't need to be fancy, but an emergency kit should contain items that can keep you alive long enough to get you home or until you can find help. Emergency kits can include items such as food, water, light sources, heat sources, clothing, radio, batteries, medical supplies, shelter, rope, knives/tools, money, solar chargers, etc. The sky's the limit! Just make sure you have one.
Charge those devices! There's nothing worse than a dead cell phone or computer when it really matters. IF cell service is available during an emergency, you are definitely going to want to have a device that is charged, and you may not be able to plug it into a wall. A solar charger or batter-powered charger is a great thing to have on hand, but play it safe by charging your devices as soon as you can when they start to get low. Unfortunately, we've become a paperless generation, which means that it is so important to do everything we can to have access to our information. Which leads us to the next tip...
Gather important documents, certificates, and information(including important phone numbers, addresses, medical info, etc.) into at least one secure location. Better yet, make copies (including digital copies) and spread them out. Keep a copy in a waterproof, fireproof safe at home; save your information to the cloud and multiple hard drives; and send a copy to your sister in Toledo.
Review your emergency plan. Know what to do in each disaster scenario. Have a plan for where to go, who to contact, and where to meet. If you have kids, make sure they know the plan. If you don't have a plan, make one!
Yep. That's right. I said laundry. Besides the threat of destruction, there might be nothing worse than a mountain of dirty laundry to do BY HAND. Keeping up on your laundry at all times ensures that when disaster strikes, you'll have at least a few days before you'll have to think about finding something to clean to wear. Laundry requires a lot of water, so chances are if your without power for more than a few days, you'll probably end up wearing dirty, smelly clothes when the clean ones run out.
And most importantly...
Being spiritually in-tune for whatever may come is THE MOST IMPORTANT thing you can do to prepare for any kind of emergency or disaster.
Elder Jeffrey R. Holland said, "We know for certain that if and when everything else in the latter days is down or dying; if governments, economies, industries, and institutions crumble; if societies and cultures become a quagmire of chaos and insecurity, nevertheless, through it all the gospel of Jesus Christ and the Church of Jesus Christ of Latter-day Saints that bears that gospel to the world will stand undefiled in God's hand until the very Son of God Himself comes to rule and reign as Lord of lords and King of kings. Nothing is more certain in this world. Nothing is more sure."
Always do what's right. If we live by faith and obedience, there is nothing to fear!