This is an old question, but I will answer it anyways. When you place a figure, you will have a statement such as
\begin{figure}
...
\end{figure}
You can specify a float placement after the \begin{figure} statement:
\begin{figure}[h]
...
\end{figure}
The [h] option will pin the figure close to where you specify it in your tex file.
[H] will pin the figure exactly where you specify it in the tex file
Other options available here:
http://en.wikibooks.org/wiki/LaTeX/Floats,_Figures_and_Captions