A tex file full of tricks for squeezing a latex document. Clearly you should avoid using these tricks. But when the deadline is near and you see no other way, you can use it to quickly change the formatting slightly to get more space. Just comment in some of the length changes or add other for the described sizes.

squeezing.tex

%% /** ---------------------------------------------------------
%%      a file full of squeezing options 
%%      -- which you should try to avoid
%% -------------------------------------------------------------
%%
%% from:
%% http://www.eng.cam.ac.uk/help/tpl/textprocessing/squeeze.html    
%% ---------------------------------------------------------- */
%%     * Page Layout
%%           o \columnsep: gap between columns
%%           o \topmargin: gap above header
%%           o \topskip: between header and text
%%           o \textheight: height of main text
%%           o \textwidth: width of text
%%           o \oddsidemargin: odd page left margin
%%           o \evensidemargin : even page left margin
%%     * Paragraphs
%%           o \parindent: indentation of paragraphs
%%           o \parskip: gap between paragraphs
%%     * Floats (tables and figures)
%%           o \floatsep: space left between floats.
%%           o \textfloatsep: space between last top float or first bottom float and the text.
%% \addtolength{\textfloatsep}{-0.0cm}
%% \setlength\textfloatsep{0.5cm}
%%           o \intextsep : space left on top and bottom of an in-text float.
%%           o \dbltextfloatsep is \textfloatsep for 2 column output.
%% \addtolength{\dbltextfloatsep}{-0.0cm}
%% \setlength\dbltextfloatsep{0.1cm}
%%           o \dblfloatsep is \floatsep for 2 column output.
%%           o \abovecaptionskip: space above caption
%% \addtolength\abovecaptionskip{-0.0cm}
%% \setlength\abovecaptionskip{0.0cm}
%%           o \belowcaptionskip: space below caption
%% \addtolength\belowcaptionskip{-0.0cm}
%% \setlength\belowcaptionskip{0.1cm}
%%     * Maths
%%           o \abovedisplayskip: space before maths
%%           o \belowdisplayskip: space after maths
%%           o \arraycolsep: gap between columns of an array
%%     * Lists
%%           o \topsep: space between first item and preceding paragraph.
%%           o \partopsep: extra space added to \topsep when environment starts a new paragraph.
%%           o \itemsep: space between successive items.


%% /** ---------------------------------------------------------
%%       AAAI specific
%% ---------------------------------------------------------- */

%% vertical size of title box
%% \setlength\titlebox{0.5in}
%% \topskip -2in
%% \abovecaptionskip 0.0in
%% \dblfloatsep -0.2in
%% \floatsep -0.1in
%% \topmargin 0.0in
%% \oddsidemargin -0.5 in
%% \abovedisplayskip 0.0in
%% \belowdisplayskip 0.0in
%% \textfloatsep 0.0in
%% \topmargin -1.0in
%% \setlength\titlebox{1.25in}
%% \setlength\titlebox{2.13in}

%% change abstract to full width (undo quote)
%% \renewenvironment{abstract}{\centerline{\bf Abstract}\vspace{0.5ex}\small}{\par\vskip 1ex}