Q:

Arrow in tikzpicture between two nodes with midway label

I'm trying to draw a series of labelled nodes in Tikzpicture, so far I have:    
\begin{tikzpicture}[box/.style = {draw, semithick, minimum size=1cm}]
  \node at (0, 3*3) [box] (0) {Node};
  \node at (0, 3*2) [box] (1) {Node};
  \node at (0, 3*1) [box] (2) {Node};
  \node at (0, 3*0) [box] (3) {Node};
  \draw (0) -> (1) node [midway, fill=white] {Label 1};
  \draw (1) -> (2) node [midway, fill=white] {Label 2};
  \draw (2) -> (3) node [midway, fill=white] {Label 3};
\end{tikzpicture}

But unfortunately I cannot figure out, despite looking on S.O and on search engines, how to get a arrow, rather than the straight line. What format should I use to achieve this?

A:

Here I put three different arrow heads in the code. You are to tell TikZ how it is supposed to draw arrows and other stuff in square brackets after \draw.
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[box/.style = {draw, semithick, minimum size=1cm}]
  \node at (0, 3*3) [box] (0) {Node};
  \node at (0, 3*2) [box] (1) {Node};
  \node at (0, 3*1) [box] (2) {Node};
  \node at (0, 3*0) [box] (3) {Node};
  \draw[->] (0) -- (1) node [midway, fill=white] {Label 1};
  \draw[-latex] (1) -- (2) node [midway, fill=white] {Label 2};
  \draw[-stealth] (2) -- (3) node [midway, fill=white] {Label 3};
\end{tikzpicture}
\end{document}

