What are small capitals? 
Shorter than the capitals of the typeface, usually the same size, or slightly taller than the x-height. Unlike all capitals, they are smaller and designed specifically to be so. 
Akzidenz-Grotesk doesn't have small caps, but Mrs Eaves does. 

Ligatures
Two letters combined into one character. A way of correcting characters that overlap, such as f and i, when next to each other. They are most commonly used when two letterforms would otherwise overlap in an unsightly manner. Such as, fi, ff, fl, and TH are a few examples. They aren't used when they are not needed, such as with sans serif typefaces, overlap of characters is unlikely or impossible.
AG does not have ligatures, but Georgia does

Foot Mark v. Apostrophe
Foot marks are a lot like an apostrophe, and look a lot like ', but are purely meant to communicate a foot. Apostrophe's are for possessive use (such as Apostrophe's) or conjunctions such as "don't" and "won't". They are not interchangeable, though, and are often confused with one another.  

Inch Mark v. Quote Mark
Just like the foot mark and apostrophe, except with " instead of '. Same rules apply, one is for measurement one is for punctuation, and the two are not interchangeable.

Hyphen, en dash, and em dashes
hyphen (-), en dash (–), em dash (—). A hyphen connects two related words, such as pre-school, or x-height. En dashes are used to separate dates such as 1834 – 1906. Em dashes function like parentheses—a form of punctuation—that allow the writer to include information that is more like another thought.