WHEN NICK ANTONELLI set out in 1947 to make his fortune, he had none of the financial clout or influential connections he would accumulate over the years. But he did have a pair of binoculars.

He moved into a rented room near the top of the Willard Hotel, high above Pennsylvania Avenue, and stared through his binoculars at the Great Plaza - a huge, government-owned parking lot stretching for more than a block behind the District Building at 14th and Pennsylvania NW.

While friends kept him fueled with coffee and sandwichs, Antonelli counted cars going in and out of the lot. He put other friends to work counting cars from a nearby sidewalk. With the information he collected, he was able to submit the winning bid for a lease from the government to operate the Great Plaza lot, thus completing his first major business deal.

Antonelli, through his PMI parking firm, has kept the Grea Plaza parking lease for 31 years now, although there was a small problem in 1971. A rival company, Monument Parking, outbid PMI for the lease that year, but PMI argued that Monument's winning bid did not contain 12 pages of a standard government lease agreement. Three weeks later, the federal government threw out those bids and solicited new ones. The second time, PMI won.

His efforts to win and keep the Great Plaza lease illustrate the thoroughness and determination that Deominic F. Antonelli Jr. has exploited to move to the top of the Washington business world.

"He's an aggressive, tough person. I think he's very smart," said Mallory Walker of the Walker and Dunlop mortgage banking firm. And, added Walker, Antonelli "plays hard - always."

Antonelli is said to know "everything about everything in his business" and even ordered a construction foreman to move an underground garage pillar because he decided cars wouldn't be able to maneuver around it.

Whatever it takes to make a deal, Antonelli's got it.

Combined with his apparently unflagging zeal for work, meticulous attention to detail and solid business reputation, Antonelli usually has right contracts in the right places and easy access to financing. He has created good will by giving generously to charity, friends and political campaigns, and opening up business opportunities to friends, associates and loyal employes. (KEY OFF)(KEYWORD)ntonelli's associates - at least those willing to be interviewed - typically praise him as "a decent human being," whose "integrity is beyond reproach." One banker said, "You'll find in the business community that people will say they would rather do business with him on a handshake than most other people on a written contract."

Most people who have done business with Antonelli describe him as reserved and almost courtly in manner. But some others have seen him in a different, more forceful mood. He once barged into the office of a government official unannounced, pounded on his desk and demanded to know what the official planned to do about a matter affecting one of Antonelli's properties.

"I don't think he's dishonest, not by one bit," sid Bedford Brown, an old friend. "He's stepped on a few toes. But he can sure turn a buck, and if you give him the chnce to do it, he will. If he gets a chance to make a dollar and somebody else is trying to make a dollar, he's going to be on top."

One Sunday morning several years ago, Antonelli was riding around town with an old friend, Jim Brown, who still works for him. Antonelli, who was reading for the comics in the newspaper, suddenly asked Brown to stop the car in front of a building. "He got out a tape measure and started making measurements," Brown said. "He ended up buying the building."

Antonelli summed up his work philosophy to Brown that day: "My competition is probably home eating breakfast now and saying to themselves, 'I'll do it Monday.' I'm here first."

It has not been necessary for Antonelli to start out quite so early in the morning to recent years, however, because of his reputation for success and influential contacts he has made at all levels of the business community and government here.

In 1970, for example, Antonelli was called by an acquaintenance who was one of the owners of an office buidling on K street NW and asked if he wanted to operate the parking garage there. Although Antonelli had not initially been invited to bid on the parking lease, he was told by his acquaintance what the high bid had been and asked if PMI would match it.

In a subsequent court deposition concerning this transaction and others, Antonelli was asked if the caller had circumvented standard bidding procedures.

"Well: I think what he was saying is, 'If you will meet the high bid, I will get it for you.'" Antonelli testified. PMI ultimately won the lease. Has Influential Allies

Antonelli has had other influential allies. He and other parking operators had two of the best contacts possible on Capitol Hill during the 1960's when Congress made all the major decisions for the District of Columbia, including whether the city would have municipal parking lots to compete with the private parking firms.

Congressional opponents of city-run parking lots and garages included two of the most powerful members of the House District Committee, then Reps. John L. McMillan (D-S.C.), chairman of the committee, and Joel T. Broyhill (R-Va.). They stripped money and authority from the city's parking authority.

They were in the somewhat inconsistent position of being big on freeways and autos but trying to choke off public parking," recalled former Rep. Gilbert Gude (R-Md.), who frequently differed with Broyhill on the committee. "Any attempt at public parking, and Broyhill was always waiting in the wings to choke it off."

Broyhill, according to newspaper stories at the time, was one of a number of congressmen and District government officials given free parking passes by the Washington Parking Association, then headed by John Lyon, a key PMI employe.

on the city's Motor Vehicle Parking Agency board, Antonelli had Lyon and another associate, W. Bruce Alexander. In 1962, both board members voted against trying to strengthen the parking agency after Broyhill and McMillan has weakened it on Capitol Hill.

By 1969, while the debate over municipal parking continued, Antonelli and Broyhill had become indirect business associates.

The American Realty Trust, an Arlington real estate investment trust on whose board of trustees Broyhill sat, took over a lease to operate the Gramercy Inn. American Realty was the tenant. Antonelli and developer Charles E. Smith signed documents as landlords.

Broyhill, who was defeated for reelection in 1974, also aided Antonelli and partner Kingdon Gould Jr. in their ultimately unsuccessful efforts to develop the old Providence Hospital site near Capitol Hill, which Antonelli, Gould and other investors owned.

When the architect of the Capitol blocked their plans to build high-rise apartments there because he planned to purchase the property for the government, Broyhill tried to intervene. In 1970, he attempted to have Congress exempt the land from acquisition by the architect. The attempt failed, and Congress voted to buy the land in 1972. Links to City Officials

Atntonelli also has forged links with D.C. officials, especially as power shifted from Capitol Hill to the District Building with home rule.

In 1969, when Sam D. Starobin became chief of the D.C. government's contracting, leasing and procurement agency, Antonelli was the first Washington businessman to invite him to lunch. Starobin said later he decided during lunc that such encounters would not be good general practice for him. He has since opposed some transactions Antonelli has attempted to arrange with the city.

Antonelli's relationship with mayoral aide Joseph P. Yeldell ultimately led to their being indicted last week on charges that bribery was involved in a decision by Yeldell to approve a 20-year, $5.6 million D.C. Department of Human Resources lease for an old vacant office building owned by Antonelli at 60 Florida Ave. NE.

Before he met Antonelli, Yeldell has said, Antonelli helped him financially, contributing to Yeldell's unsuccessful 1971 campaign to become the first nonvoting delegate to Congress from D.C. The two finally met in 1973, when Yeldell, who was then DHR director, sought Antonelli's advice about a financialy troubled travel business in which Yeldell was a partner.

Yeldell and his partners borrowed $21.500 for the businss from Madison National Bank, of which Antonelli is a major stockholder. Antonelli guaranteed that loan for Yeldell several times, even after it fell far in arrears, and later made a $33,000 loan to Yeldell, according to the criminal indictment.

The indictment also alleges that Antonelli was able to obtain a confidential city "talking paper" that revealed the maximum legal rent the D.C. government could pay for the Florida Avenue property. Antonelli used the document to see k financing on the building.

As a landlord who, with his partners, collects millions of dollars in rent from the government, Antonelli has frequently come into contact with the General Service Administration in a relationship that has shifted with the market.

"There was a time a couple of years ago when we had much more control," said Hilar Richards of GSA's regional space management division here. Rents were lower then.

"Under current market conditions, it's very difficult to negotiate" with Antonelli and other landlords, she said, especially when agencies are in place in privately owned buildings and don't want to move. "When you get right down to it, they (the landlords) know what the market is. I'm sure the (landlords) are chuckling to themselves." Federal Government Contacts

In 1971, when an Antonelli partnership was negotiating to lease space to a federal agency in one midtown office building, one of the GSA bureaucrats it dealt with was James Blondell. His job, in general, included making appraisals, drafting leases and participating in lease negotiations, according to GSA officials.

At GSA then, proposals from the Antonelli partnership arrived marked for special attention of Blondell. Now, Blondell works as an attorney for Antonelli and signs lease negotiation letters to GSA on Antonelli's behalf.

Antonelli's corporate attorney, Mitchell Blankstein, also came from an agency with which Antonelli dealth, the Internal Revenue Service. he was hired away from the office of the IRS chief counsel to help with PMI's tax problems, although his duties have since expanded.

Antonelli's business interests are so varied and so numerous, and the number of people with whom he has done business so great, that it is hard for him to move around Washington without bumping into a former business associate or contact.

In the early 1970's, when Antonelli's PMI got involved in a three-way legal battle over a federal lease building that wound up in the U.S. Court of Appeals, the judge who ruled on some routine prehearing motions was Chief Judge David Bazelon, who has been a limited partner in at least one Antonelli venture.

Representing PMI in the dispute, which also involved a group of developers and GSA, was attorney John Risher, who later became D.C. corporation counsel.

Antonelli also has acted on the maxim that it helps to have a friend at the bank. He does business with many financial institutions, including Madison National Bank, where he is on the board of directors. As of June 30, 1976, according to a bank proxy statement, Antonelli and his associates had $4.49 million out on loan from Madison, an amount equal to more than 10 percent of the bank's equity capital accounts.

A check of land records showed nine loans totaling $585,000 from Madison National Bank to Halifax Square Associates on the same day in November 1976; a $160,000 Madison loan later than month to 900 G Street Associates: a $350,000 loan in February 1977 to Greyhound Associates Limited Partnership, and a $400,000 loan that same month to Alpine Associates. All are Antonelli ventures.

Questions have been raised about whether so much of the bank's money should go to an insider. A Washington Post investigation in early 1976 found that directors, stockholders and former employes of the bank and their relatives and businesses had received all but one of the real estate loans of $100,000 or more made by Madison in Washington during a three-year period.

Madison's current president K. Donald Menefee said recently that Antonelli is a major depositor, "brings us good loans on which we make good income" and sometimes pay above the market rate for loans "because of his loyalty to the bank." Charitable Contributions

Some of Antonelli's clout has to do with giving rather than getting money. His corporate and private fortunes have helped bankroll political campaigns, the Catholic Church and the Boy Scouts, for whom his parking firm has founded Camp PMI near Goshen, Va. Antonelli also has helped old friends when they were down on their luck.

Antonelli contributed $16,125 in 1972 to former President Richard Nixon, while his PMI partner Gould, contributed $100,900. Gould was later named by Nixon as ambassador to The Netherlands. In 1976, Antonelli gave $1,000 to Gerald Ford. He has also contributed to Texas Rep. Earle Cabel when he was on the House District Committee, former Rep. Broyhill and former Maryland Rep. Lawrence Hogan.

Locally, Antonelli has contributed to election campaigns of Mayor Walter W. Washington, city council members Sterling Tucker and Jerry Moore and losing D.C. congressional delegate candidates Yeldell and William Chin Lee.

"He gives to charity than anyone knows about," said one business partner, and a competitor praised Antonelli's work for the local cancer society.

Antonelli also provides jobs for old friends and his or their relatives, brings them and business associates into money-making ventures and makes or cosigns loans for them. "It's his way of saying, 'You do a good job, and I'll give you tidbits,'" said a former business associate, who added, "He always lets them know he's the one helping them out."

Antonelli, at age, is clearly still a man determined to get what he wants, someone for whom work is the obsession of most of his waking hours. Friends say he can't relax, because behind the now wealthy and successful businessman is the street kid working almost as hard as before.