In different place the distance between items under enumerate or itemize option

Question

In different place the distance between items under enumerate or itemize option. Please suggest to set them uniformly as all things in 1.5 line space as my draft.

Answer 1

You can set the space inside an itemize environment.

\documentclass{article}

\begin{document}

\begin{itemize}
  \setlength{\itemsep}{18pt}
  \item test
  \item test
\end{itemize}

\end{document}

It is also possible to use baselinestretch.

\documentclass{article}

\begin{document}

\renewcommand{\baselinestretch}{1.5}\normalsize
\begin{itemize}
 \item test
 \item test
\end{itemize}
\renewcommand{\baselinestretch}{1}\normalsize

\end{document}

If you want to change the space in the whole document, you can simply add these two lines before document environment and change the 18pt to any value you want.

\let\OLDitemize\itemize
\renewcommand\itemize{\OLDitemize\addtolength{\itemsep}{18pt}}

The best solution is to use the enumitem-package.

\documentclass{article}

\usepackage{enumitem}
\setitemize{itemsep=18pt}

\begin{document}

\begin{itemize}
\item test
\item test
\end{itemize}

\end{document}

Now you can change the itemsep-value to any value you want.

To change the item space in bibliography only, you can add this to your preamble.

\usepackage{natbib}
\setlength{\bibsep}{18pt}

If it doesn't work, you can also try this:

\let\oldbibliography\thebibliography
\renewcommand{\thebibliography}[1]{%
\oldbibliography{#1}%
\setlength{\itemsep}{18pt}%
}

Answer 2

I think this is what you want.

\documentclass{article}
\usepackage{enumitem}
\usepackage{kantlipsum}
\usepackage{setspace}
\onehalfspacing                %% <--- Better use setspace
\setlist[itemize]{nosep}       %%% <--- no extra separation
\setlist[enumerate]{nosep}     %%% <--- no extra separation
\begin{document}
\kant[1]
\begin{itemize}
  \item test
  \item test
    \begin{itemize}
        \item test
        \item test
        \item test
    \end{itemize}
  \item test
\end{itemize}
\kant[2]
\begin{enumerate}
  \item test
  \item test
    \begin{enumerate}
        \item test
        \item test
        \item test
    \end{enumerate}
  \item test
\end{enumerate}

\end{document}