LaTeX - formatting - utilizing vertical space - \vspace

Again, I was adjusting the look of my CV using the \vspace command because there were extra spaces between section headings, an horizontal line, and the first entry of the section like so:

Here is that section of code:

\section*{Employment} 
\HRule 
\begin{itemize}
\item \textbf{Graduate Research Assistant}
\item University of Tennessee Space Institute, Tullahoma, TN
\item November 2011 - Present
 \begin{itemize}
 \item AFRL Prime Contract No. FA9300-06-C-0023
 \item Assisted major advisor who was a reviewer for journal papers in critiquing and writing summaries
 \item Assisted major advisor in building and proofreading research grant proposals
 \end{itemize}
\end{itemize}
\HRule
\begin{itemize}
\item \textbf{Graduate Research Assistant}
\item University of Tennessee Space Institute, Tullahoma, TN
\item August 2006 - May 2011
 \begin{itemize}
 \item Worked on AFOSR grant No. FA9101-06-D-0001/0003, Advanced High-Speed Propulsion Development; Out of the grant I produced and presented one AIAA conference paper and my MS thesis in Aerospace Engineering

So I tightened it like this:

\section*{Employment} \vspace{-5 mm}
\HRule \vspace{-6 mm}
\begin{itemize}
\item \textbf{Graduate Research Assistant}
\item University of Tennessee Space Institute, Tullahoma, TN
\item November 2011 - Present
 \begin{itemize}
 \item AFRL Prime Contract No. FA9300-06-C-0023
 \item Assisted major advisor who was a reviewer for journal papers in critiquing and writing summaries
 \item Assisted major advisor in building and proofreading research grant proposals
 \end{itemize}
\end{itemize}
\HRule \vspace{-6 mm}
\begin{itemize}
\item \textbf{Graduate Research Assistant}
\item University of Tennessee Space Institute, Tullahoma, TN
\item August 2006 - May 2011
 \begin{itemize}
 \item Worked on AFOSR grant No. FA9101-06-D-0001/0003, Advanced High-Speed
Propulsion Development; Out of the grant I produced and presented one AIAA conference paper and my MS thesis in Aerospace Engineering

So little things like this make LaTeX, IMO, very versatile/customizable and small changes can make big differences in looks.