The standard way to do double spacing which everyone recommends as
clean and neat is to use the setspace package since it doesn't
double-space your footnotes which is generally desired.
Turns out that (a) this isn't the typographical standard of double-spacing (b) it's not the same as Microsoft Word which everyone else's extended essays/dissertations/theses will be written in.
So instead use this:
\usepackage[doublespacing]{setspace} \setstretch{2}
and if you change the spacing be sure to do it again:
\singlespacing [...] \doublespacing\setstretch{2}
(source)
