1) have a job.
2) stick to the portfolio I suggested(http://web.wenxuecity.com/BBSView.php?SubID=tzlc&MsgID=38801). This will give you a return of 25% YTD.
There is no US stock bubble. It will go up reasonably.
The lowering rate, burst of RE bobble, lowering exchange rate all point to a healthier, better US economy in the long run.