BTW, one common mistake I see, one which I made myself when I first got my 28/3.5 PC-Nikkor, is to overcorrect for converging verticals.

It's natural to see converging verticals with tall buildings. The eye expects it. By overcorrecting these lines from ground level using a shift lens or camera movements we create a perspective that doesn't exist in nature. It looks odd.

A better method is to gain elevation. That's why you'll see photos of Ansel Adams working from the roof-mounted platform of his vehicle when photographing Yosemite and other favorite spots - he was trying to gain just a little more elevation to prevent having to overcorrect with the camera.