Good question for me I have a small bag that I transfer between packs for backpacking hunting or snowshoeing and then I add to for winter.
I have in no order a couple of light sticks, flint and steel and waterproof matches and a candle I also have some little packs of military fire starter. My matches are in a whistle match holder a space blanket a tube shlelter a wire saw and a small first aid kit along with a small signal mirror. In a small water proof plastic bag and cell phone...
I always carry some food and extra water in my pack I also carry a small cheap plastic painters tarp for laying meat on and it can be used for a shelter in a pinch. Along with a compass and GPS. I some times hunt by my self and when I do I make sure my partner knows where I will be which in the coast range is fine you are not going to be very far from a road. If I am in Eastern Oreogn in I always have a map with me.
I carry a space blanket bag & space blanket. Matches in waterproof container & a few lighters-fire starter-emergency whistle-xtra TP-foot care products(mole skin)-gps-flashlight or headlamp-xtra batteries. I always carry rope/twine-knives-H20-food & topo map of area in my general hunting gear depending on area and species. Rarely carry cell phone(turned off) - most times cannot get reception. Don't forget to replace matches-lighters-even your space blankets as I had not done that for a few years and opened mine up and they fell apart. Some folks take a book or something to read if stand hunting and it may also help calm them down if they have to stay a night or two out.
The idea is to keep your survival gear pack handy so that means small & light so you'll always take it with you! You have to use some common sense when putting your kit together and adjust your gear for needs that you anticipate - hot weather/cold weather issues and the like. It needs to consist of items that will help you deal with medical emergencies and stay warm & dry for a few days. I always carry a map, compass, flashlight and knife on my person so let's start there. The items in my pack include the following:
Small First Aid Kit (for minor things plus some butterfly strips)
Several ways to make fire (small lighter, waterproof stick matches, flint striker)
Fire starter (commercial or home made)
Plastic poncho (to cover up)
Space blanket (to sit/lay on)
Large garbage bag (ground cover, poncho, shelter roof, etc..)
Parachute cord (big jobs)
Dental floss (small jobs)
Whistle (you can hear it a lot farther than a shout and you never get tired of blowing it) 2nd Flashlight (small L.E.D.)
Besides a lot of ideas already mentioned on this board, I've gotten into the habit of almost always having an augmented pocket survival pack on me, whether fishing hunting kayaking or whatever. Definitely learned my lesson the one time I had to hike out of the upper wind river on a kayaking trip gone wonky.