Safe Ways to Boost Yield?

From the Wall Street Journal

The reality is that the only way to boost yield is to take more risk. But if investors play it smartly, they can improve their returns without having to buy subprime mortgages - and they will know all the risks going in.

The article describes an "advanced" strategy to boost yields by creating a portfolio of Treasuries, TIPS, Municipals, short-term corporates and stocks. It also describes a "simple" strategy with less risk that includes bank accounts, I Bonds and short-term bond funds. A fund manager proposed the "advanced" portfolio. It seems "investment experts" rarely include bank accounts as a sizable part of one's portfolio.