Sometimes a friend or acquaintance will bring up the subject of Wall Street with an eye toward taking a plunge in the stock market.

While I am not a stockbroker, I never hesitate to share my thoughts on the subject with anyone who asks.

When the stock market was showing jitters over the North American Free Trade Agreement just before the U.S. House of Representatives voted to approve it recently, my advice was "buy, buy, buy!"

It wasn't until the day after the vote, when the market was taking a dive, that someone told me I should have known better: Everyone knows you buy on the rumor, sell on the news. Now they tell me!

A very attractive stock, not long ago, made millionaires out of dozens of its employees and big bucks for hundreds of wise investors. Everybody liked the stock, and I suggested that anyone who wants to make a killing should get on the bandwagon right away. The stock dive-bombed to less than 20 percent of its high, and a lot of folks lost their shirts.

It wasn't until the stock hit bottom that I learned the age-old philosophy of clever market watchers: When the average guy is buying, you sell; when the average guy is selling, you buy. Too late now!

There was one stock that I knew I couldn't lose on. When I found out that the company's earnings had quadrupled, I advised the stock should be bought immediately. Everyone knows it's a company's earnings that drive up the price of a stock. But, alas, the stock tumbled the day the earnings report came out. Despite the incredible improvement, earnings came in below the estimates of Wall Street analysts. Now I know: Improved earnings aren't everything!

One of the world's biggest companies was obviously in deep trouble earlier this year when it announced record losses and divestiture of its most important and profitable subsidiaries. Naturally, my advice was: Get rid of this lemon posthaste. You guessed it, after only a brief interlude, the stock moved substantially higher, bringing lucrative profits to those who are made of sturdier stuff.

A longtime market leader was selling near its all-time high some months ago, and I read in U.S. News and World Report that this traditionally strong company, with a good dividend, had excellent prospects for improved earnings. The company's balance sheet was solid as a rock, and its management was good. Naturally, I told friends that this was a good buy for anyone looking for capital gains.

Believe it or not, I was wrong because not long after I offered this free advice the company announced it was having trouble with its competition; things didn't look so good, so it would have to make dramatic price cuts -- a big drag on profits. That's how I learned that you can't believe what you read in the magazines -- and you can't go only by the balance sheet either.

Over the last couple of years, and particularly over the last few months, almost everyone has been talking about how good an investment the technology stocks are. The future of stocks dealing with computers, telephones and cable television is sure to be a bright one. I advised buying a top stock in the field, and only a few weeks later that dog took a nosedive.

My advice? Try the horses!

This is a column I penned as a "My View" for The Hour newspaper of Norwalk, Conn., on Nov. 17, 1993.