Styling an "article" document

Question

I'm writing a document using the class article. There are some things I'd like to change, for example:

• Always center \section and \subsection titles without doing it manually each time using \begin{center} ... \end{center}
• decrease the spacing between list elements without writing \begin{enumerate}[itemsep=-1mm] each time.
• etc.

Where can I find instructions about this? I couldn't find a "manual" where I could look up all of the options and keys. In case there is not a manual, how could I achieve these results?

Answer 1

For customizing sectional units you can use the sectsty package (for relatively "minor" changes) or the titlesec package; for customizing list-like environments, you can use the enumitem package; both enumitem and titlesec are very well documented and the documentations include numerous examples. Here's a little example illustrating the changes you mentioned in your question:

\documentclass{article}
\usepackage{titlesec}
\usepackage{enumitem}

\titleformat*{\section}{\centering\bfseries\Large}
\titleformat*{\subsection}{\centering\bfseries\large}

\setlist[enumerate]{itemsep=-1mm}

\begin{document}

\section{A test numbered section}
\begin{enumerate}
\item First item.
\item Second item.
\end{enumerate}
\subsection{A test numbered subsection}
\subsection*{A test unnumbered subsection}
\section*{A test unnumbered section}

\end{document}

The above approach applies mostly to standard document classes (book, article and report); other classes (memoir or the ones from the KOMA-Script bundle) have their own mechanisms; it should be noted, for example, that memoir or the KOMA-Script classes and titlesec are incompatible (See About memoir and titlesec incompatibility and Incompatibilities between KOMA-Script and titlesec).

Just for completeness's sake, I'll add one possible solution to both problems mentioned in the question but using the memoir document class. As I said before, now it's not advisable to use titlesec to customize the sectional unit headings, but to use the features provided by the class; I used the article class option and the prdedefined crosshead chapter style to get centered titles for sections (now produced using \chapter) and used \setsecheadstyle to center the subsection titles (now produced using \section); enumitem is still used to customize the enumerate environment:

\documentclass[article]{memoir}
\usepackage{enumitem}

\chapterstyle{crosshead}
\setsecheadstyle{\centering\bfseries\large}

\setlist[enumerate]{itemsep=-1mm}

\begin{document}

\chapter{A test numbered section}
\begin{enumerate}
\item First item.
\item Second item.
\end{enumerate}
\section{A test numbered subsection}
\section*{A test unnumbered subsection}
\chapter*{A test unnumbered section}

\end{document}

Using scrartcl from the KOMA-Script bundle, again using titlesec is not advisable, but you could use \sectfont instead:

\documentclass{scrartcl}
\usepackage{enumitem}

\renewcommand\sectfont{\centering\bfseries}
\setlist[enumerate]{itemsep=-1mm}

\begin{document}

\section{A test numbered section}
\begin{enumerate}
\item First item.
\item Second item.
\end{enumerate}
\subsection{A test numbered subsection}
\subsection*{A test unnumbered subsection}
\section*{A test unnumbered section}

\end{document}

As I used \sectfont, the changes will also affect subsubsections.

Finally, if you want to apply the changes to the amsart document class, you will only have to change the subsection formatting (section titles are centered by deafault in this class); the change can be done by redefining \subsection as implemented in amsart.cls, or using titlesec (as in the first example since titlesec is compatible with the AMS-family of document classes), or by patching this command with the help of, for example, the etoolbox package. A little example (lists have a more tight vertical spacing in this class so I left the modification commented):

\documentclass{amsart}
\usepackage{enumitem}

\makeatletter
\def\subsection{\@startsection{subsection}{2}%
  \z@{.5\linespacing\@plus.7\linespacing}{.5\linespacing}%
  {\normalfont\bfseries\centering}}
\makeatother
%\setlist[enumerate]{itemsep=-1mm}

\begin{document}

\section{A test numbered section}
\begin{enumerate}
\item First item.
\item Second item.
\end{enumerate}
\subsection{A test numbered subsection}
\subsection*{A test unnumbered subsection}
\section*{A test unnumbered section}

\end{document}