Auto is fine. Manual is fine. But you're not going to see any improvement in either unless you understand exposure.
The only reason why Greystar and Derrel, or myself and Jake337 get good results using whatever exposure mode we prefer is because we understand exposure and camera control. The rest is just process and preference. But manual exposure alone doesn't make you a better photographer and auto exposure doesn't make your pictures any better.
I've never really understood why exposure, in and of itself, is difficult. Especially if you're not using lights, and don't have to deal with how shutter speed differentially treats ambient v. flashed light.
What do people mean when they say 'understand exposure'? I really don't get how any old idiot can't just get a properly exposed photo.
Do people mean understand, artistically, what they want their exposure to be? Because that can be hard. But that doesn't seem to be what people mean by 'understanding exposure,' when they talk about it here.
how is it not just as simple as:
ISO - higher values make the picture brighter, lower values darker
Aperture - bigger numbers (putting aside the whole fraction v. whole number debate for a second) mean darker, lower numbers mean brighter
shutter - shorter shutters mean darker, longer shutters mean brighter
After that, you only need to understand the concept of a stop, which is pretty easy (though perhaps f/stops take a bit of memorizing, but are still relatively straight forward if you just remember the main ones, ie 1.4 -> 2 -> 2.8 -> 4 -> 5.6 -> 8 -> 11)
Flash complicates things a little bit, but when people here talk about 'understanding exposure' they are almost never talking about flash either.