• Remove the calls to packages that are not essential to reproduce the problem (e.g., \RequirePackage, \usepakage)

• Remove the local definitions that are not essential. For instance, use
  \begin{figure} 
     \includegraphics{filename} 
     \caption{What ever.} 
  \end{figure} 
  

  instead of

  \def\fig#1#2{\begin{figure} \includegraphics{#1} \caption{#2} \end{figure}} 
  \fig{filename}{What ever.} 
  

• Use core classes when possible (e.g., article instead of scrbook).

• Cut to a minimum the content where possible (e.g., ‘Abc’ instead of ‘Blah blah ... for ever.’)

I work in a LaTeX environment different from where the bug reports typically originate. To understand the bugs I need to recreate the environments producing them. A sample file that isolates the problem reduces the debugging effort to a minimum.