\makeatletter   % the 'at' sign is now a normal "letter" for TeX

% Redefine the \section{} and \subsection{} to be smaller and use less space:

\renewcommand{\section}{\@startsection
{section}%                      % the name
{1}%                            % the level
{0em}%                          % the indent
{-0.10\baselineskip}%           % the beforeskip
{0.25\baselineskip}%            % the afterskip
{\normalfont\large\bfseries}}%  % the style

\renewcommand{\subsection}{\@startsection
{subsection}%                   % the name
{2}%                            % the level
{1em}%                          % the indent
{-0.25\baselineskip}%           % the beforeskip
{0.10\baselineskip}%            % the afterskip
{\normalfont\bfseries}}%        % the style

\makeatother    % the 'at' sign is restored as a "non-letter" for TeX