1: times package-- use Times New Roman font, can be used to save page space
   Usage: add line \usepackage{times}  % use times to save space if needed


2:  balance package--  automatically make the reference in the last page
balanced
    Usage: step (1): add line \usepackage{balance}
           step (2): add \balance just before the bibliography.

Example:
\balance
\bibliographystyle{abbrv}
\bibliography{biblio}

  with this package, we do not have to manually modify the generated .bbl
file to make the reference balanced.

3: nowidow package--no widow at the begin/end of each page
   Usage: add line \usepackage{nowidow}

   with this package, we do not have to manually modify the text to make
widow disappear.

4: tabularx package--cre­ates a para­graph-like col­umn
   Usage: add line \usepackage{tabularx}

tabularx de­fines an en­vi­ron­ment tab­u­larx, an ex­ten­sion of
tab­u­lar which has an ad­di­tional col­umn des­ig­na­tor, X, which
cre­ates a para­graph-like col­umn whose width au­to­mat­i­cally ex­pands
so that the de­clared width of the en­vi­ron­ment is filled.

   Example: \usepackage{tabularx}

\begin{table}
\caption{Table caption \label{tab:table_label}}
\begin{tabularx}{\linewidth}{ c X }
    text in the first column & more text in the second column\\
\end{tabularx}
\end{table}