Shares market crashed

Let's talk about shares. It has gone down about 20 over percents average for all global bourses from London FTSE, France to Asia Hang Seng Index, Tokyo Nikkei, Singapore STI, Shanghai, India, Australia etc...

How to pick a good stock?

I believe in fundamental. One measurement I like is BVPS.
(http://www.investopedia.com/university/ratios/bookvaluepershare.asp)

Book Value Per Share - BV

=	Stockholders Equity - Preferred Stock
	Average Outstanding Shares

It will be rare and you will be lucky to find one share that is trading below this figure.
In theory this is what is the valuation of a company but Mr Market never rate it such way and prices are usually driven by demand and supply and also emotional.