Read on ...
There are times when you need to work quickly but still do so in a considered way, the art of work quickly slowly as you might say.
One such time is when working in extreme environments or extremes of weather conditions like when it is freezing cold and the light is failing fast. Then, despite being wrapped up warm, prolonged exposure to the conditions can take their toll especially to digits exposed to operate camera controls. Indeed "brain fade" can set in if you are trying to do dexterous things like change films (if you are a film photographer) just to add to the "fun".
So the secret is to do as much of the considered part as possible in advance by presetting your camera to avoid having to think about this stuff when out in e.g. the cold.
Thus I will load up a fresh colour negative film of the appropriate speed, preset the aperture (typically f8) if it for out doors work. I set the shutter to "A" for aperture priority to let the camera take care of shutter speeds for me and the film's very wide exposure latitude handle any variance.
The lens I am most like to use the most for that particular subject/shoot goes onto the camera body. Note: I use prime lenses mostly, very rarely zooms so this advise is written around the use of prime lenses. For focus I will use zone aka hyperfocal distance focusing by pre-setting the focus distance, using the scale engraved upon the lens barrel, against my chosen aperture.
Having done all of that in advance, all I have to do is to work quickly concentrating only on framing my composition and pressing the shutter release. Wind on and I'm ready for the next picture.
Finally, to avoid having to reload the camera in extremis so to speak often I carry a second body also pre-loaded and set up ready to go; this body may sometimes have second lens attached if I think it will be needed in combination with the first. Typically I will carry a 35mm and 90mm duo - seems to be a favourite of mine - but not exclusively so, depending on the subject of the shoot.
So there you have it, the art of working slowly quickly. Gosh, it was bitterly cold that day.
There again I could simply "cheat" and use my technologically more sophisticated Contax G2 with its automated film loading, winding and rewinding, DX coded film speed setting and electronic rangefinder AF. It does shine when you want to work quickly with precision, though with its ability to run at up to 4 frames per second you can burn your way through film in an unconsidered way and at an alarming rate if you are not careful.