\documentclass[12pt]{article}
%---include different packages-----------
%\usepackage[dvips]{graphics}
%\usepackage{color}
%\usepackage{graphicx}
%\usepackage{latexsym}
%\usepackage{amsfonts}
%\usepackage{amssymb}
%\usepackage{amsthm}
%\input psfig.tex

%----define page layout------------
%****************************newcommands*********************
\newcommand{\bi}{\begin{itemize}}
\newcommand{\ei}{\end{itemize}}

%****************************definitions*********************
\def\title #1{\begin{center}{\Large {\bf #1}}\end{center}}

\baselineskip=16pt \topmargin -1.5in \oddsidemargin -20 pt
\evensidemargin -20 pt

\setlength{\textheight}{750pt} \setlength{\textwidth}{450pt}

%**************************begin document**************************

\begin{document}

\vspace*{4mm}


\title{\LaTeX\, Examples: \\ Itemize}
 \vspace*{10mm}

\begin{itemize}
    \item This is the first line.
    \item This is the second.
        \subitem If I had something more to say about the second
        line, it could go here.
        \begin{itemize}
        %\bi
            \item If I got stuck on a tangent, it may be important
            enough to be given its own subheadings.
            \item And I might ramble on for a while \ldots
        \end{itemize}
        %\ei
    \item And so on \ldots.
\end{itemize}


\end{document}