You've gotten some great advice! Here is some more.

1) Make sure a fire is legal, smart, and you really need one.
2) Practice on your bbq grill at home, in yucky, wet weather.
3) Carry matches or a lighter, not a a "fire steel". Matches skip a step and give instant fire with kindling, any altitude.
4) Make up some "fire bunnies"...tightly wadded paper towels saturated in paraffin (gulf wax). These work better than dryer lint, light quickly, burn for about 10 minutes, weight very little, and cut building time. Birthday candles are handy too.
5) Take your time. Spend a good 30-45 minutes gathering tender, kindling, and fuel, all ready to go for ignition.
6) Have an emergency "extenguish plan"!!! Jug of water, dirt, whatever. Don't make fires bigger than what you need and can handle. Sparks can (will) get away and even light dry tree canopys so THINK!

I consider items 6) and 2) most important. If you can get a fire going in cold, wet, uncomfortable conditions, you can do it anywhere, but you also need to be able to put it out.