well digital imaging has changed things for sure. Used to be a 5x7 was a good size, and snapshots were even smaller. but when you have a 21 inch screen you see problems that would not be noticed on a smaller scale.
And the photoshop type programs are pretty cool, but it takes a lot of work with them to get the effects subtle enough. I think at first I went overboard, but I've got better at using them to a minimum, rather than to the max.
I think second was that he told me to start to create studies. Things that I almost had a fetish about. So for me its graveyards and lights, a bunch of lights at one of my jobs I have taken thousands of shots of, and keep on working at them. But like the graves, I have gone in the morning, afternoon, dusk, hot sunny days, in rain, and work on not only taking the shots, but trying to understand how the conditions change the image.