At the Arlington County Fair, the unofficial start of fall electioneering, Rep. Frank Wolf (R-Va.) strolled through the maze of booths, glad-handing prospective voters.

Walking in step, two feet behind him, was a young man in a beige suit with a handful of yellow campaign fliers, who stopped while Wolf chatted with voters and waited patiently for the two-term congressman to introduce him.

"Frank has been very helpful and has given me a lot of advice. We do Metro stops together, we did the county fair together and we've had two fund-raisers together," said Peter Espada, the man in the beige suit and a candidate for the Arlington County Board. "Just people's knowledge that he's supporting me has really helped me financially."

The 33-year-old Espada says that he is going to need all the help he can get in his first bid for public office: a race against popular Arlington County Board Vice Chairman John G. Milliken, a Democrat seeking his second four-year term in the Nov. 6 election.

Espada, a Republican-backed independent who is an economist with the General Accounting Office, says that he is trying to raise $30,000, against the $40,000 the Milliken camp is seeking.

He also is going to have to try to assemble a precinct organization to rival the successful one that has helped put the board's sitting Democrats in office over the years. Some Republicans have said that the lack of such an organization in their camp has been their party's Achilles' heel.

In addition to the Democrats' precinct operation, Milliken also will have the active support of many county teachers, who have put together a formidable coalition of volunteers over the years.

On Milliken's motion, the board has appropriated extra funds for the schools in the last two years in which the Democrats have been the majority, money to "enhance the teaching profession" as the School Board saw fit and to boost the pay raises of senior teachers beyond the amounts that had been proposed.

To help raise funds and gain name-recognition, Espada has called upon Michael E. Brunner, the board's only Republican, and former GOP board members Dorothy T. Grotos and Walter L. Frankland Jr.

Although some Republicans, who asked not to be named, expressed the opinion that Milliken is unbeatable, Espada said in a recent interview that he no longer believes the campaign will be an uphill struggle against the 39-year-old Milliken, who is a partner in the law firm of Winston and Strawn, the firm with which Democratic presidential contender Walter Mondale is associated.

Espada says that that he has found in his campaign to date "a level of dissatisfaction with the County Board majority."

He says most of the complaints that he has heard are nonspecific, but that, in his visit to the county fair several people approached him to complain about the board's decision to grant extra retail space at the Pentagon City shopping mall above the amount approved by a 1976 board in consultation with nearby residents. Milliken insisted that the extra space include a specified number of convenience stores to serve the nearby residents.

The board unanimously granted the extra retail space only after demanding cuts in hotel space at the site and elsewhere on still undeveloped Pentagon City land so that the overall project and the mall site followed the 1976 standards. Espada says that he would have voted with Brunner to support Democrat Albert C. Eisenberg's unsuccessful motion to cut some of the extra retail space, as some nearby residents wanted.

Although he faults Milliken for not supporting Eisenberg's motion, Espada has found that Milliken has been on the losing side of some votes passed with the support of the other three Democrats. As a result, Espada is focusing some of his attacks on the board's majority instead of on Milliken.

One of Espada's campaign leaflets, for example, criticizes the majority for defeating, 3 to 2, a Brunner motion to delay action on opening a temporary shelter for homeless men in a residential neighborhood that was undergoing massive redevelopment near the Court House. Brunner wanted to wait until other nonresidential sites could be found.

Espada says that he would have supported Brunner's motion. His literature did not mention that Milliken had seconded the motion and voted for it.

"The majority isn't necessarily a partisan one. But I am part of the majority and proud of it," says Milliken. "I think he wants to have his cake and eat it, too. He wants to run against the majority on issues he disagrees with the majority on and happens to agree with me. On other issues, where he disagrees with me, he'll simply disagree with me.

"His opponent is me. And so, by necessity, he's going to have to compare his positions and views with mine, since that's the basis on which people will vote."

Both candidates agree that the issues will be the perennial ones: protecting residential neighborhoods from the encroachment of development, keeping the tax rate low, providing adequate funding for schools and county services, preserving neighborhood-oriented businesses, and expanding the county's supply of affordable housing.

As chairman of the Metro transit board, Milliken has come under some attacks from Espada for the system's spiraling costs over the years. Milliken has said that his major objective as Metro chairman is to control and pare costs, a goal that is difficult but attainable on the regional body. The chairman, he says, "can't rule by fiat."