What About Fonts?
Serif and Sans-Serif
Serif: "A fine line finishing off the main strokes of a letter, as at the top and bottom of M." --Dictionary.Com


Serif fonts are generally easier to read in print, as the serif's make the characters easier to identify. The old typographers spent much time proving this by actual experiment. However, a proviso is that sans-serif fonts look better on lower-resolution computer screens. They are simply easier to read.
A common convention is to use a serif font for the body of your document and a sans-serif font for the headings.
Fixed and variable width fonts
Older
printers, teletypes and monitors began with fixed-width fonts. This means
each character was exactly the same width. This was because that was all
the technology of the time could produce.
This
is distinctly different than virtually all printed material. Look closely
at a page from a magazine or book, and you will see that the distance
between the characters differs from character to character. Thus, the
horizontal space required by an "i" is different than that required by an
"m".
As monitors and printers became more sophisticated, they started to support variable width characters. Nowadays, fixed-width characters are only used by programmers (for their code) and reporting.
Kerning
Kerning: "To adjust space between (characters) in typeset text." --Dictionary.Com
A step up
from variable-width characters is called kerning. This means the width of
each character is adjusted depending upon the characters to either side.
Thus, the characters are shoved together as much as they can.
Why is
this done? It tends to make the text on the page look more professional
and more can fit on a page. It is, however, much more difficult for
software and hardware to support kerning. In addition, the font software
must be very sophisticated.
In general, kerning is done on material that is intended to be printed. It is not done by web browsers or many word processors.