When setting up your survival system, you must prioritize what you need and in what order to obtain it. Unless you are independently wealthy, you will probably need to put together one piece at a time. Most survivalists go by the “rule of three” which states that you can survive 3 minutes without oxygen, 3 days without water, and 3 weeks without food. This of course is the maximum and the human body experiences many adverse effects not long into these durations. The whole point of preparing is to avoid having to go without for anywhere near this long, especially in a long term scenario.
Not only do you have to take the physical necessities into consideration, but also which scenario is most likely to occur in your area. In addition, you need to keep your climate into consideration. If you live in Phoenix you will need to consider water much more than if you live in Seattle. You also should determine which components are the most versatile. You can use a standard “72 hour kit” for both bugging out (leaving your current area temporarily or permanently to seek a better environment during a disaster) or bugging in (sheltering in your current place while riding out a disaster).
My recommendation is to start with the 72 hour kit if you have absolutely no preparations. A 72 hour kit, as covered elsewhere on this site includes 3 day worth of supplies. This includes 3 days of food, water, clothing, heat, emergency shelter, etc. http://www.nationalterroralert.com/72hourkit/ has a great list of a basic 72 hour kit. A very important aspect is that the kit should be mobile in case you have to leave your area.
The upgrade to the 72 hour kit is called the “bug out bag” which usually includes similar items to the 72 hour kit, but includes a more rugged pack and wilderness survival items. Youtube user ryanjcus has one of the best basic wilderness survival kits I have seen. Here is a link to the video: http://www.youtube.com/watch?v=pvz1o9qkzDs As for the bag itself, usually people go with either a military style ALICE or MOLLE pack, or they just use a civilian backpacker’s pack. Survivalcache.com has a great list of additional items your bug out bag will need. http://survivalcache.com/bug-out-bag/
After getting together your mobile gear, the next step is your general sheltering in place supplies. You probably want to start with working up to a one month supply of food and water and then work your way up to 3 to 6 months. Water is essential, 1 gallon per person, per day at absolute minimum. Food should have a long shelf life and be rotated as necessary. Start with canned goods, moving up to MRE’s, freeze dried, and dry goods storage to extend the life of your stores.
You will also want to think about other items you would need in a long term survival situation such as: hygiene items, books(with knowledge you’ll need such as homesteading), sanitation, weapons (for self defense or hunting), communications gear (short wave, walkie talkies, CB radio, “HAM” Radio), rechargeable batteries and a solar method of charging them… The list goes on and on.
Continue this process and look to have an edge in any situation, from flat tires to a total breakdown of society.