Many photographers have their own personal style, their own
way of setting up their camera, below are examples of just a few.
1. Shoot in Aperture 'Av' mode, setting your iso to 100 and your
aperture to f/5.6 then monitor your shutter speed and adjust
your aperture and iso accordingly.
2. Shoot in Shutter 'Tv' mode, set Tv to 1 - 2 times the lens focal
length i.e for 50mm lens set the Tv to 1/50 - 1/100 seconds
then set the iso to auto and the camera adjust Av for you.
3. Manual mode where you adjust the Tv, Av, and iso to suit the
scene.
4. Program mode ,Do Not miss that once in a life time shot, leave
the camera in program mode and just concentrate on
composition, once you have taken the photograph the switch
to Av mode or Tv mode which ever you prefer and then adjust
your settings to suit the scene.