My stock portfolio is most about trying to capture tiny slices of ownership in the dominant publically traded companies in the world (in most sectors and industries) and not overpaying for that little piece of future earnings. I want to pay at most fair-valuation (although sometimes I try for bargain prices) as long the company appears solid and I think the company will be around 10 years and more. That is what I found produce the best total returns. I am mostly focussed on mature companies that pay dividends, but I do make exceptions, for leading companies in some industries - even if their dividend yield is low. I appreciate diversification and risk-management by not putting too much cash into each stock.
My portfolio has a spreadsheet on http://tiny.cc/tarkin
Evaluation of the dominant assumptions and an understanding of the dynamics of the economic engine is the basis of an approach to asset allocation that provides for both a rational determination of value and an understanding of sentiment in the form of price as a measure of the irrational nature of the operational environment, an approach that is intended at once to avoid unnecessary risk while at the same time enable gradual rebalance of assets as a means to increase net worth via optimization of appreciation and long term yields. Let's call that buy low and fly high just for fun.