>>3188167Aperture priority mode is fine for a beginner. Auto ISO is not. Unless you have your max set to about 800 (depending on the camera but I'm assuming you're using something cheap).
Even then you'd want to know how to change it quickly.
Aperture priority changing ISO manually is generally a safe bet if you either don't understand exposure or don't trust your ability to nail it.
If you're shooting in daytime, a flash won't always look awful (though I generally avoid it)
Exposure compensation could allow you to underexpose the subject but generally I'd try to expose correctly for the subject and bring the sky back later. Or somewhere in between.
I'd rather an over-processed sky than an over-processed subject.
