What do you need to get first?

There are many different scenarios and each one has a different starting point.. For example, If you live in a disaster prone area, you need to look at the types of  natural disasters you have, and what is the most common thing to go out first. If you are just starting, and have nothing yet,  keep this in mind..

Necessity-

1) Water: Store bottled water, re-use empty milk jugs, get a portable water filter because you will need it when you are on the go,The human body cannot go without water for more than 2 days, if you live in a warmer climate and sweat the time is shortened depending on how much water you lose. That would be a first priority.

2) Food:  "The duration of survival without food is greatly influenced by factors such as body weight, genetic variation, other health considerations and, most importantly, the presence or absence of dehydration.
For total starvation in healthy individuals receiving adequate hydration, reliable data on survival are hard to obtain. At the age of 74 and already slight of build, Mahatma Gandhi, the famous nonviolent campaigner for India's independence, survived 21 days of total starvation while only allowing himself sips of water. In a 1997 article in theBritish Medical Journal, Michael Peel, senior medical examiner at the Medical Foundation for the Care of Victims of Torture, cites well-documented studies reporting survivals of other hunger strikers for 28, 36, 38 and 40 days. Most other reports of long-term survival of total starvation, however, have been poorly substantiated. [Editor's Note: Reports of the 1981 hunger strike by political prisoners against the British presence in Northeast Ireland indicate that 10 individuals died after periods of between 46 and 73 days without food.]"
Courtesy:http://www.scientificamerican.com/article.cfm?id=how-long-can-a-person-sur
Our Govt keeps our personnel very active in training and in the field. Because of that, they are on a daily 2000+ calorie food intake so their bodies have the fuel to make the energy to go out and kick the crap out of Al-Qaeda. In times of active stress and a rebuilding scenario. We need as many calories per day to replace the ones we burn, so our bodies can  make the energy we need to keep going. So when you store food, you need to know the  amount of you are putting away to store, Shelf life, and rotating it, so the newest is in the back. Remember to keep it fresh and tolerable when you need it, there is an old prep rule: "Eat what you store, and store what you eat. " when storage food get close to it's limit and your funds are too, you don't want to throw away perfectly good food but, want to keep adding to your preparations. If it does get down to that, eat the older stuff and buy newer to replace it. That way you are still eating, AND keeping your food stocks up to date! It's a win-win!
Now, knowing you will be eventually eating your food stocks what do you want to have in them? Do you want all "Brussels Sprouts and Lima Beans.. Or do you want foods you can enjoy too? Don't stock foods you don't normally eat.. I myself, love Beef Stroganoff, Garlic Mashed Potatoes, and Macaroni and Cheese :)). SO far all of it is available dehydrated for Long-Term  Storage (LTS)! Instant Mac and cheese,  mashed potatoes, and canned Garlic Powder for starters,  and my sponsors "just add hot water" Dehydrated Mountain House: Beef Stroganoff! Or,.. you can look it up in MREs on the site.. You want to keep foods you know you will enjoy eating, Especially if you DO get in a disaster scenario, wouldn't you want to lessen the blow, with some foods you enjoy?
Shelter: You want to stay out of the elements, the rain, too much Sun and more. Invest in a Tent, small tarp or even large heavy trash bags. If you have nothing else you can make a trash bag rain catcher, rain coat, or even  rain-proof a stick-and-leaf small temporary roof! There are many things you can think of in a desperate situation.  I know from experience.. you can get pretty creative when you need to.
Learn to see in the dark: Venture around your house more often in the dark, learn to pick out and identify shapes. You can train yourself to see better without light in case of a power outage. Remember, flashlights are a "Here I am"  beacon to anyone wanting to steal what you have, or harm you and yours, the less light you need to function in the dark the better. Eliminating your absolute need for light in the dark may save your life.
Learn to listen to your surroundings in the dark: I cannot stress this one enough, you need to pay attention to every little noise, creak,step, breath, and rustle. Knowing the sounds and what makes them in a split seconds thought. I have found that even silent light makes "noise".. as ridiculous as it sounds try it, go outside at night when it is darkest and listen to every sound you can hear then, step under a street light a few feet away and listen again. You will notice you don't hear all of the sounds you heard in the darkest areas.
Practice these and learn what you can. I will return tomorrow with more.

'Til then.. Be Safe and Happy Prepping!