Like this, only it doesn't work:
\documentclass{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw [->] (0, 0) ellipse [x radius = 2, y radius = 3];
\draw [->] (0, 0) -- (1, 0) -- (0, 1) -- cycle;
\end{tikzpicture}
\end{document}
(Edited, twice, to include an MWE that actually compiles, as requested).
\begin{tikzpicture}and\end{tikzpicture}. Second, I think you have to use thedecorationslibrary. See for instance TikZ: How to draw an arrow in the middle of the line?. – Peter Grill Apr 14 '15 at 20:28decorationslibrary did the trick, as explained in the other question. – nemarona Apr 15 '15 at 16:27