NEW YORK (TheStreet) -- Investment advisor and bestselling author John Spooner is hoping the Millennial and Gen X generations take his advice -- and not just financial advice. He's released a new book, No One Ever Told Us That: Money and Life Lessons for Young Adults.

"The book is for new grown-ups, out in the world for long enough to have experienced some early bumps in the road, and long enough to know how challenging the new century can be," says Spooner.

A prime piece of Spooner's investing advice is that "technology changes, fads change and buzzwords change, but human nature never does." With that in mind, he tells his audience to look for out-of-favor sectors and start building positions in stocks before they inevitably come back around.

"Four years ago I looked for the most hated list and one of the most hated sectors was health care and big pharma. Lots of stocks trading at new lows," said Spooner. "I overweighted those stocks and collected healthy dividends while I waited for them to come back into vogue."

Of course, they eventually did, with health care becoming the best-performing sector of the S&P 500 (SPY) in the past 5 years. Right now Spooner is seeing a similar distaste in the market for natural resources names, as well as financials, which "remain the most hated group by the public," in his opinion.

"Cycles are immutable. Sooner or later oversupply turns to demand, and the banks will come back too," said Spooner.

As for hard assets, Spooner advises his readers not to confuse precious metal investing with buying jewelry, saying "the price of gold is one thing and jewelry is another."

"You buy a nice piece of jewelry for $1,000 and when you eventually try and sell it they give you $400 or $500. Then they will mark it up back to $1,000 again and the cycle repeats itself," said Spooner. "Never buy jewelry for an investment unless you are Elizabeth Taylor."

As for the current market, market veteran Spooner offered a trio of reasons to buy on the dips.

"Interest rates are at record lows. Even if they go up a quarter of a point, it does not matter. Second, the level of anxiety is high in America, and I'm not seeing greed -- I want to be in the market. The third thing is that there are trillions of dollars on the sidelines earning nothing in money funds that are ready to come back into the market."

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