Latex

Only include what's used. A short, tidy preamble is better than a dumping ground of commented-out packages.

Tables — booktabs + siunitx

Always use booktabs rules. Never \hline.

\begin{tabular}{l S[table-format=2.3] S[table-format=2.3]}
\toprule
              & {OLS}   & {Poisson} \\
\midrule
Treatment     &  0.142  &  0.153    \\
              & (0.031) & (0.034)   \\
Control mean  &  1.240  &  1.240    \\
\bottomrule
\end{tabular}

• Decimal alignment: use siunitx S columns with table-format=X.Y. X is digits to the left of the decimal, Y to the right. Headings and non-numeric cells in an S column must be wrapped in {...}.
• parse-numbers=false lets cells contain pre-formatted numbers or stars for significance, at the cost of automatic alignment — the S-column still aligns on the explicit decimal point in the source.
• Use \addlinespace for visual grouping within a single table rather than extra rules.
• Avoid vertical rules. If a reader needs a separator, reach for \cmidrule(lr){2-4} or a grouped \addlinespace.

Captions and notes

• Captions go above tables (set once with \captionsetup[table]{position=top} or use fig-cap-location: top in Quarto).
• Keep captions to one sentence. Put explanatory detail in a \tblnote{...} immediately after the tabular environment but before \end{table}.
• For long/landscape tables, sidewaystable (from rotating) is usually enough; use pdflscape only when you also need the page itself rotated.

Figures

• \usepackage{graphicx}; \usepackage{float} if you need [H] to force in-place placement.
• Captions go above figures (\captionsetup[figure]{position=top}) when the venue allows — otherwise below.
• Put detail in a \fignote{...} directly after the \includegraphics line, inside the float environment.

Math

• amsmath, amssymb, amsthm are the minimum.
• Use \DeclareMathOperator{\OpName}{OpName} rather than redefining primitives like \exp, \log, \Pr. Collect operator declarations in one block near the top of the preamble.
• Define project-specific shortcuts (e.g. \E, \Var, \Cov) as operators or via \newcommand — don't redefine existing math primitives.

Bibliography

• Default to natbib with aer style: \usepackage[authoryear, sort&compress, round]{natbib} and \bibliographystyle{aer}.
• Use \citet{} for textual citations (Author et al. (2022)) and \citep{} for parenthetical citations ((Author et al., 2022)).
• For two bibliographies (e.g. main paper + online appendix), use multibib:

  \usepackage{multibib}
  \newcites{App}{Online Appendix References}
  \bibliographystyle{aer}
  \bibliographystyleApp{aer}
  

• For .bib file conventions — entry types, field order, author formatting, citation keys — see the separate /bibtex skill. That skill is the authoritative source for anything inside a .bib file.

Appendices

Appendix top-level sections should display as "Appendix A", "Appendix B", etc., but subsections should remain "A.1", "A.2" (no "Appendix" prefix). Figures and tables are numbered within each appendix and counters reset at each new appendix.

\cleardoublepage
\bibliography{refs}

\cleardoublepage
\appendix
%  Display section as "Appendix A", subsections as "A.1", "A.2", ...
%  Tables and figures numbered within appendix (A1, A2, ...).
\renewcommand{\thesection}{\Alph{section}}
\renewcommand{\thetable}{\thesection\arabic{table}}
\renewcommand{\thefigure}{\thesection\arabic{figure}}
\makeatletter
\renewcommand\@seccntformat[1]{%
  \@ifundefined{my@appendix@#1}{}{Appendix~}%
  \csname the#1\endcsname\quad}
\@namedef{my@appendix@section}{}
\makeatother
\setcounter{table}{0}
\setcounter{figure}{0}

\section{First appendix title}
\label{app:first}
...

\cleardoublepage
\setcounter{table}{0}
\setcounter{figure}{0}
\section{Second appendix title}
\label{app:second}
...

Notes:

• Put a \cleardoublepage between appendices and reset the table / figure counters so numbering restarts as B1, B2, …
• \thesection is just \Alph{section} — the "Appendix~" prefix is added only to the displayed section heading, via \@seccntformat. This keeps in-text references clean: write Appendix~\ref{app:first} and it renders as "Appendix A", not "Appendix Appendix A".
• The \@ifundefined guard ensures the prefix is applied to sections only, not subsections. (If you later add a named sub-environment that should also get the prefix, \@namedef{my@appendix@<envname>}{} adds it to the allow-list.)
• If the document has a single appendix, still use \@ifundefined + \@namedef — that keeps subsections like "A.1" unprefixed.

Editing-phase packages

• todonotes for inline editing marks. Set a small textwidth ([textwidth=0.9in]) and a muted colour so todos don't dominate the margin. Remove all \todo{...} calls before a ship-ready build.
• comment if you need large commented-out blocks (safer than % on every line).

Spacing and page setup

• titling for fine-grained title positioning (\setlength{\droptitle}{-6em} to pull the title closer to the top).
• setspace for line spacing: \onehalfspacing for drafts, \singlespacing for tables / footnotes / abstract, \doublespacing only when a venue requires it.
• Standard margins: margin=1.125in (conference / working-paper) or margin=1.5in (double-spaced manuscript style).

Don't

• Don't use \hline — use booktabs rules.
• Don't use \begin{center}...\end{center} inside floats — use \centering.
• Don't load subfigure (obsolete) — use subfig or subcaption.
• Don't load both subfig and subcaption in the same document.
• Don't load hyperref before cleveref / natbib — hyperref goes last.
• Don't redefine \exp, \log, \Pr, etc. — use \DeclareMathOperator.
• Don't use $ ... $ for display math — use \[ ... \] or an equation/align environment.

Cross-references

• \ref{} for numbered things, \eqref{} for equations, \citet{} / \citep{} for citations.
• Label prefixes by type: sec:, subsec:, app:, tbl:, fig:, eq:, assn:, thm:. One consistent prefix scheme makes \label{}/\ref{} pairs scannable.

Related skills

• /bibtex — conventions for .bib entries (entry types, field order, author formatting, citation keys, DOI handling). Use this skill whenever editing or creating .bib entries.
• /quarto — conventions for .qmd documents rendered to PDF or Beamer. Those conventions mirror the LaTeX conventions here but are expressed through the Quarto YAML header rather than a preamble.
• /makefile — conventions for Makefiles that build LaTeX and Quarto documents.