1: A good survival kit should be compact, lightweight, and portable.
After all, what good is a survival kit that you can't actually TAKE anywhere? And the smaller, lighter, and more compact it is, the better. When a kit is smaller and lighter, the easier it will be to take with you or pack in a backpack, bag, or piece of luggage.
2: It should contain at least the minimum things required in an emergency(fire, water, food, shelter, and tools).
And the more items in the kit that are multi-taskers, the better. Multi-taskers are a survivalist best friend since they perform multiple duties, reduce weight and size of the kit, and are handy for many different situations.
3: It should be fairly inexpensive and easy to replace.
Sure you can go out to a survival store and spend hundreds of dollars on the highest end survial equipment that they have to offer. And sure it will really work. But, with a little imagination and ingenuity, you can create a good, solid survival/emergency kit with minimal cost that will work just as well, if not better than the expensive sport shop items. With some things cheaper isn't always better (such as multi-tools and axes), but for the most part, the less expensive a kit is, the more you will be able to put in it
Now, with that being said I feel that everyone should have 3 kinds of survival kit in their life. The "Personal" survival kit you carry with you always like the flames from your first love. The "Travel" kit that you shove inside of a backpack, suitcase, or bag. And finally the "Emergency" kit that IS the suitcase, backpack, or dufflebag that you grab when disaster strikes. Below are my opinions on the basic guidelines each of these kits should have. I will go into greater detail on each of these types of kit, but that is another episode.
The Personal Survival Kit
The first kind is one I like to call the "Personal" survival kit. This survival kit is the one that a person can carry around with them all the time. Since it has to fit in a pocket, purse, or other small container on your person, it can't contain very much. Which is why, WHAT you put in this kind of kit becomes all the more important. So with this kind of kit only the barest of bare essentials should be included. You should try to have something that you can use to start a fire with (such as a lighter or book of matches), a good multi-tool or knife (such as a keychain swiss army knife), and a short wooden pencil and a few small sheets of paper (bank deposite slips work wonderfully for this).
All of this can fit inside of a mans wallet or pocket fairly easily. A book of matches and a couple of sheets of paper can fit in the inside pockets of almost any size wallet. An unsharpened small pencil can be carried in the pocket fairly easily and can be sharpened using the multi-tool or keychain pocketknife, plus the shavings can be good firestarting tinder. Many multi-tools or cell phones have good belt sheaths. These can also hold other items like a folded up garbage bag or a piece of cardboard with a few feet of duct tape wrapped around it (especially if they have a pocket or other compartment on it).
Ladies have a slightly easier time since a purse is naturally suited towards containing a good personal survival kit and should contain even more survival essentials like a whistle, a mirror, and napkins/tissue.
Now of course, trying to take knives, multi-tools, and lighters/matches on airline flights is both risky and illegal so don't do it. However, most airline stores or nearby gas stations carry the above items, so as soon as you land, restock your personal survival kit (hence another reason why your survival kit should be inexpensive).
The Travel Survival kit.
This survival kit is the one that most of us think of when we think of survival kits. It should be under 5 lbs and easily fit in a backpack, suitcase, dufflebag, or large purse/carry all. This kit should contain everything you will need to survive in the wilds for at least a week in almost any environment. It should contain at least the following; A lighter or matches, a good multi-tool, small portion of food (a king sized candy bar, a bag of beef jerky, a granola or energy bar, etc.), a small first aid kit (band aids, gauze, alcohol swabs, etc.), a 33 gallon black or orange garbage bag, a pen, unsharpend pencil, a pad of paper, a signal mirror, a compass, a whistle, water purification tablets, a small roll of duct or eletrical tape, a small medication bottle (if you take medicine, if not put tylenol, anti-diarretics, and antacids in it), plastic utensiles, and extra pair of socks and underwear.
All of this can easily fit inside most large heavy duty ziplock bags and can be placed in a small box or cloth bag so you can carry it wherever you go while hiking, day-tripping, or travelling. An example of my own travel sized survival kit can be found here;
The Emergency Kit
Or the "Bug Out" bag as it is sometimes referred to as. This kit should contain everything you will need to survive a disaster of some kind. It should weight less than 50 lbs and fit inside of a dufflebag or suitcase. It should have at least the following in it; A blanket, two changes of clothing, a rain poncho, a travel survival kit (see above), personal care kit (toothbrush/toothpaste/deoderant/etc.), a larger first aid kit, A canteen (preferably metal), a good filet/butcher knife (disregard if going on a flight), a book, additional food, and some rope or cord of some kind, flashlight, a larger roll of duct tape, and a sweater, gloves, and stocking hat. It would also be a good idea to include copies of important documents in a waterproof bag (SS card, birth certificate, insurance information, important phone numbers, etc.)
All of that should easily fit inside of large dufflebag or suitcase and can easily be grabbed and taken with you in the case of an emergency. If you are travelling in your own car, then your trunk should also have a good tool set, a 3 gallon jug of water, a hatchet or axe, and a tarp.
I hope you have enjoyed this episode of Good Survival and that these suggestions and tips will be useful to you and just remember...
It's better to have it and not need it, than to need it and not have it.