In Latex, in order to put small vertical space between abstract and Index terms or keywords (or anywhere in the document) in a conference or journal paper or article, add :
\vspace{space height} e.g. \vspace{0.5cm}, \vspace{1cm} etc.
The image below shows the latex pdf file without using \vspace{} between abstract and Index terms
The image below shows the latex pdf file after \vspace{0.5cm} between abstract and Index terms
The code for the above pdf file is (after omitting the packages and all)
\begin{document}
\title{freemindscafe.com is a Great Site!}
\author {\IEEEauthorblockN{Smita Singhal, Nikhil Agrawal}
}
% make the title area
\maketitle
\begin{abstract}This is to create a vertical space
\end{abstract}
\vspace{0.5cm}
\begin{IEEEkeywords}
space, document, freemindscafe
\end{IEEEkeywords}
\section{Introduction}This is test introduction
\label{Int}
\end{document}