It may have seemed, to the casual onlooer, like the most routine of business in the Virginia House of Delegates the other day. The honorable gentlelady from Fairfax had taken the floor to offer an innocuous amendment to a minor bill dealing with delinquent property taxpayers.

But when Del. Vivian E. Watts (D-Fairfax) finished her maiden speech as a Virginia lawmaker, she found herself surrounded by supportive colleagues who rushed to her side and offered their congratulations. "Very impressive," said one senior delegate grabbing her hand. "Great job, freshman Delegate Watts," echoed Del. Bernard Cohen (D-Alexandria), another in a long line of well-wishers. "That was quite a first move."

The reason for this small celebration was that Watts had managed to accomplish in just two weeks in Richmond what takes many legislators several sessions: She had persuaded the House to adopt one of her amendments. True, it was small potatoes as amendments go. It required counties to notify persons less than $5 in arrears on their tax bills before their names are relased to the newspapers in the annual lists of delinquent taxpayers. Watts said she was concerned that these taxpayers would be needlessly embarrassed by the exposure and she wanted to give them another chance to clear their accounts.

"I'm really quite pleased by this," said Watts, a veteran citizen activist who had ridden the Trailways bus down from her home in Annandale only a few hours earlier. "This shows how, if you're really willing to work hard and if you're constructive, you can build up some respect here and get things done."

In a General Assembly governed by a revered committee system that rewards longevity as the ultimate virtue, earnest newcomers like Watts tend to be overlooked. That is especially true when they come to the capitol with large agendas and ambitious proposals to reform the Commonwealth. But the willingness of Watts, a past president of the Fairfax County League of Women Voters, to learn the rules of the game and make small contributions is a formula for at least modest success. And it already has set her apart from some of her predecessors from Fairfax.

Until a few short months ago, for example, the citizens of southern Fairfax were represented here by Lawrence D. Pratt, a citizen activist of another sort. A firebrand "New Right" partisan, Pratt had once formed a group called the Gun Owners of America because he believed the National Rifle Association wasn't vigilant enough in fighting to preserve and protect the Second Amendment's right to bear arms clause. In Richmond, he had mostly distinguished himself by introducing a bill to ban the display of nudity in public--a proposal which, had it been adopted, would have forbidden the display of the partly-clad woman on the Virginia state seal.

Pratt, like his ideological twin John S. Buckley, who also was defeated in November, had come to the General Assembly more to score ideological points than hammer out legislative compromises. "Both of them came down here enraged about certain things, and that was one of the reasons for their ineffectiveness," says Watts. "They totally isolated themselves. I believe to come down here and slap the desk is insulting to legislators who have tried to grapple with some of these issues for a long time. There's a phrase that I believe has a lot of validity: 'Don't insult the crocodile until you've crossed the river.' "

And so Watts acknowledges that she has already lowered her sights somewhat for the legislative session. She had defeated Pratt at the polls in November on a platform that included increasing state funding for public education and road programs in Fairfax and stricter health and safety inspections in industry, especially at construction sites in Northern Virginia where some workmen have been killed. The latter proposal smacks of "government regulation," a perpetual menace to the conservative barons of the General Assembly, as well as the state's construction lobbies.

Although Watts says she will be introducing legislation on these issues, she has little expectation it will pass. Instead, she says, she intends to concentrate her firepower on a "little bill" of hers to allow four-way stop signs at traffic intersections in Fairfax County. So far, the highway department has been stubbornly opppsed, but Watts is determined.

"The issue is rational enough," she said the other day, still basking in the glory of her first legislative triumph. "I'm going to get my way on this one."