\documentclass[12pt]{article}

% set smaller margins
\usepackage[a4paper,margin=1in]{geometry}

% use standard math symbols
\usepackage{amssymb}

% for \text inside formulas and for \eqref
\usepackage{amsmath}

% enable full XeLaTeX power
\usepackage{xltxtra}

% select widely available fonts
\setmainfont{Times New Roman}
\setmonofont{Courier New}

\usepackage{xeCJK}
\setCJKmainfont{Heiti SC Light}

% set paragraph margins
\setlength{\parindent}{0pt}
\setlength{\parskip}{6pt plus 2pt minus 1pt}

% prevent overfull lines
\setlength{\emergencystretch}{3em}

% for \includegraphics
\usepackage{graphicx}

% for exact placement of figures
\usepackage{float}

% for footnotes in tables
\usepackage{longtable}

% for hyperlinks
\usepackage[colorlinks,urlcolor=blue,filecolor=blue,linkcolor=black,citecolor=black]{hyperref}
\usepackage[all]{hypcap}
\urlstyle{same}

% do not number sections
\setcounter{secnumdepth}{0}

\begin{document}

$body$

\end{document}