Section hierarchy organizes documents. Articles use \section{Title} (level 1), \subsection{Title} (level 2), \subsubsection{Title} (level 3). Books add \chapter{Title} at level 0. Sections are automatically numbered and appear in the table of contents. Use the starred version \section*{Title} for unnumbered sections not in the TOC.
\section{Introduction} Content here. \subsection{Background} More content. \subsection*{Unnumbered subsection} This doesn't appear in TOC. \section{Methods}
Lists are environments for bullet points or numbered items. itemize creates bullet lists, enumerate creates numbered lists, description creates term-definition pairs.
\begin{itemize} \item First point \item Second point \begin{itemize} \item Nested point \end{itemize} \end{itemize}
renders as a bulleted list with nested indentation.
\begin{enumerate} \item First step \item Second step \item Third step \end{enumerate}
renders as a numbered list: 1, 2, 3.
\begin{description} \item[Term] Definition of term. \item[Another] Its definition. \end{description}
renders as a term-definition list.
Nesting works by indenting one list environment inside another. The automatic numbering and bullet styles adjust (bullets become dashes, then asterisks at deeper levels). Limit nesting to 3-4 levels for clarity.
Labels and cross-references let you reference sections, figures, and tables by number. Place \label{key} after the section or caption, then use \ref{key} to insert its number:
\section{Introduction} \label{sec:intro} In Section \ref{sec:intro}, we showed...
The reference is updated automatically if you move sections. Compile twice for references to resolve.