k0xxx said:
SKR8PN is spot on with the Blast Matches. They are great.
Take some cotton balls, infuse them with petroleum jelly and store them in a "zip lock" bag. They are light, and start easily with a blast match or other flint and steel type devices. The also burn surprisingly long. They're a excellent addition to a BOB.
Small, flexible Fresnel lenses are great also for sunny days. I keep one in my wallet, as well as in our BOB's and 72 hour packs in the car. You don't have to worry about breaking them, like with a glass magnifier. They also work quite well as intended for reading menus, and other fine print when I forget my glasses.
Edited to correct FFS (Fat Finger Syndrome)
Not sure what a blast match is but I carry two things in my BOB. The first is the old magnesium block with flint on the side. Works really well, is very light and does not give a rip for day/night or wet/dry conditions. Magnesium burns really hot and will start wet wood if pushed.
The other thing I carry is for sunny days. It was called a "Solar Cigarette lighter" and I got it some years ago for just this purpose. It will definitely light a cigarette on a sunny day. (I don't smoke but finding cigarette butts has always been easy). The cotton ball and petrolatum jelly works very well. The limitation here is the number you can carry and for how long do you prepare?
Any magnifying glass will work, but of course you need good sunlight and great tinder. The magnifying glass on the Swiss Army Knife does work if you are patient enough and take your time.
Of course, there is the possibility of being in an environment where you have significant ice. It is true that you can start a fire with ice but the technique involves shaping it into a lens with your hands...takes some getting used to but it IS possible.
Dryer lint is great with the 9 volt battery as mentioned above but eventually the battery runs down and then you have to find another or come up with some other way.
Cottonwood was mentioned and is without question the best for starting a fire using a bow/drill. In his book Tom Brown mentions this fact. If you don't have cottonwood, knowing how to use a bow/drill puts you at an advantage. You can make it anywhere you are (perhaps except the desert) and it will perform beautifully for an indefinite period of time. I would however, recommend that you try it a few times before you consider it as one of your armamentarium. It can be daunting at first, but eventually, you will get it.

The cottonwood fluff, dryer lint, very finely ground up paper, etc. will assist you in getting started.
The
tinder you use is the key to the whole thing. The finer it is, the greater your chances of getting fire started before your hands turn to a bloody pulp.(see Cast Away with Tom Hanks...he learned the hard way)

The second most useful item is an accelerant. Pine trees yield a good option. Fatwood is great, too!
As for leaning, there are unlimited videos on YouTube on any subject you could imagine. Some good, some fantastic. All are helpful and done by folks who mean to help. We may talk about these skills here but seeing them is really helpful for learning them.
Nothing works better than the technique with which you are most familiar. Stick to what works. Stashing butane lighters is good but don't leave them out. Keep them in an airtight container. The gas will eventually leak, but also the flint will deteriorate after a number of years. I particularly like the butane lighters with the long stem and piezo-electric sparkers...I use that to light my corn stove and it does wonders for keeping your fingers from being sinnged.
Hope you find this helpful.
Best to all
Trim sends