Rules of Thumb?

Getting exposure right is a science.
The art lies in using your choice of
ISO and shutter speed to the best advantage.

I've taken to metering off my hand, a tip learned
from reading, but reinforced by a chat with a photographic
expert in town. Flower colours seem more vivid, as a result.

And now that sharp Spring sunlight is here at last,
the Sunny 16 rule can be used to good effect.
Details are in the link in the Title Bar.