By Roberto Pedone
Posted on Nov. 27, 2009

According to Jim Cramer, investors need to know the four enemies of all bull markets. On Wednesday’s “Mad Money” TV show, Cramer reminded viewers that all bull markets must come to an end. However, he said the key to investing successfully is to sell your stocks before that happens.

With this in mind, he pointed out some key things for investors to look for so they can avoid any looming selloff. One warning sign that investors should look for is inflation. Cramer said inflation has killed almost every bull market since he started his career on Wall Street. He explained that inflation usually means the Fed will raise rates, which can hurt earnings and force investors into high-yielding securities over stocks.

Another problem to watch for is “super extreme valuations” in stocks. Cramer reminded viewers that stocks were so overvalued in 1987 and 2000 that earnings per share were put on the back burner to sales per share, takeover potential and future earnings. Cramer said if you see this, you have to get out of stocks because you will get slaughtered.

Cramer said another issue that can lead to the end of a bull run is if the market loses its leadership stocks. He mentioned that in 2007 and 2008, one leader after another started to collapse and trade lower. Cramer said when this happens the followers begin to sell off, so investors have to pay attention to the action in market leaders.

Finally, Cramer told viewers to watch out for high unemployment. He said jobs are key to any bull market because two-thirds of the U.S. economy is a consumer economy, so without job growth we can’t sustain a bull market. Cramer warned investors that a jobless rate over 10% will stop a market rally cold.

Recently, Cramer found opportunity in three tech stocks, nine stocks that work right now and stocks that have been hit with absurd selling. Here are some Cramer highlights from over the past week as aggregated from his "Mad Money" TV show, the "Stop Trading!" segment on CNBC and his RealMoney blog posts (these blog posts might require a RealMoney subscription).

Cramer’s 3 Tech Names in Bull Mode: Cramer highlighted three tech stocks that he believes are in bull-market mode. In a Nov. 23 blog post, he wrote: “I think that those who are worried about being underexposed to this market should begin to leg into these stocks now with a bet that you can build them up this week amid some sporadic weakness.” The Cramer’s 3 Tech Names in Bull Mode portfolio includes Apple (AAPL) and Google (GOOG).

Cramer’s 9 Stock Buys: Cramer highlighted nine stocks that investors should get in right now. On last Thursday’s “Mad Money” episode, he told viewers to forget about the averages and start investing in stocks on a case-by-case basis. The Cramer’s 9 Stock Buys portfolio includes Monsanto (MON) and Nordic American Tanker Shipping (NAT).

Cramer’s Trade-to-Yield Stocks: Cramer sees opportunity in buying dividend-paying stocks. In a Nov. 25 blog post, he wrote: “This trade to yield, which is also going on with the utilities, comes at a time when you can't get anything good out of the bond market.” The Cramer’s Trade-to-Yield Stocks portfolio includes Verizon Communications (VZ) and Intel (INTC).

Cramer’s Absurd-Selling Stock Buys: Cramer thinks the bad news out of Dubai has produced some absurd selling in a number of stocks. In a Nov. 27 blog post, he wrote: “The arithmetic's pretty funny when you think of it -- we go down as much as Europe's minus from Thanksgiving and plus from last night, even though we shouldn't be as hostage given our lessened exposure. And isn't it puzzling that we didn't go down more on Wednesday when it was known Dubai was in trouble?” The Cramer’s Absurd-Selling Stock Buys portfolio includes Coca-Cola (KO) and Transocean (RIG).

Cramer’s Good Earners at Bargain Prices: Recently, Cramer recommended that investors look to buy stocks with solid earnings at bargain prices. On On last Friday’s “Mad Money” episode, he told viewers he’d be a buyer of ag stock Deere (DE) for a play on a global recovery and a weaker dollar. The Cramer’s Good Earners at Bargain Prices portfolio includes J. Crew Group (JCG) and Hewlett-Packard (HPQ).

Cramer’s Puzzling Stocks Cramer thinks some bizarre things are going on in the market. In a Nov. 25 blog post, he wrote: “Railroad carloadings are extremely strong but Baltic Freight is weak -- a total conundrum that's hard to figure out. I will err on the side of the railroads because oil tanker rates keep going higher.” The Cramer’s Puzzling Stocks portfolio includes Chesapeake Energy (CHK) and Best Buy (BBY).