Latex distinguishes between three different enumeration/itemization environments. Each of them provide four levels, which means you can have nested lists of up to four levels.
Enumerate:
\begin{enumerate}
\item ...
\end{enumerate}
The enumerate-environment is used to create numbered lists.
If you like to change the appearance of the enumerator, the simplest way to change is to use the enumerate-package, giving you the possibility to optionally choose an enumerator.
\usepackage{enumerate}
...
\begin{enumerate}[I]%for capital roman numbers.
\item
\end{enumerate}
\begin{enumerate}[(a)]%for small alpha-characters within brackets.
\item
\end{enumerate}
Itemize:
\begin{itemize}
\item ...
\end{itemize}
Itemization is probably the mostly used list in Latex. It also provides four levels. The bullets can be changed for each level using the following command:
\renewcommand{\labelitemi}{$\bullet$}
\renewcommand{\labelitemii}{$\cdot$}
\renewcommand{\labelitemiii}{$\diamond$}
\renewcommand{\labelitemiv}{$\ast$}
Amongst the more commonly used ones are $\bullet$ (
$\cdot$ (
$\diamond$ (
$-$ (
$\ast$ (
$\circ$ (
Description:
\begin{description}
\item[] ...
\end{description}
The description list might be the least known. It comes in very handy if you need to explain notations or terms. Its neither numbered nor bulleted.
Example:
\begin{description}
\item[Biology] Study of life.
\item[Physics] Science of matter and its motion.
\item[Psychology] Scientific study of mental processes and behaviour.
\end{description}
And in a PDF it would look like this:
Example of a description list.
Note:
The space between different items can be controlled with the \itemsep command (can only be added just after “begin”):
\begin{itemize}\itemsep2pt
\item
\end{itemize}
