Example for the standalone package. For http://istitov.wordpress.com/2013/03/14/standalone-latex/

my_image.tex

\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}
\draw (0,0) circle (0.4cm);
\end{tikzpicture}
\end{document}

myfile.tex

\documentclass[a4paper,10pt]{scrartcl}
\usepackage{tikz} %needed to satisfy build dependencies of the included graph 
\usepackage{standalone}
\begin{document}
\begin{figure}[p!]
\input{my_image} %inputting the picture itself
\caption{That's it!}
\label{fig:standalone}
\end{figure}
\end{document}