Rules to investing? I look for only 2:

1) Tax efficiency and effectiveness: ie. seeking companies on the basis that they pay a dividend is foolish and forgoes any rise in capital gains (the book value vs share value)

2) Follow great investors: and not your financial adviser. So you pretty much can't go wrong reading about Warren Buffet or John Bogle, especially for the small investor point of view. The 2 open admit going in a low cost index ETF for long term growth is a for sure winner. If you are trying to pick individual stocks, you begin to play the SAME game as manage funds like Kiwi Saver (as those managers are trying to pick individual stocks).