These may also be called smart quotes or typographer's quotes. Don't leave large text unkerned. In word processing software, you normally can't manually kern text, but you can turn kerning on over a certain point size. Don't center large amounts of text. Centering is fine for a few words or a headline.
Nothing screams amateur like a headline set in all caps in a calligraphic font.
Upper and lowercase letters help people read faster. All capital letters should be used sparingly. Don't leave widows and orphans. A widow is a paragraph whose last line is at the beginning of a column of text. An orphan is a paragraph whose first line starts at the bottom of a column of text.