West Virginia Gov. John D. (Jay) Rockefeller IV came across the mountains tonight and offered advice to Virginia Democrats about what he knows best -- how to use modern techniques, including lots of television advertising, to win elections.

Rockefeller told Lt. Gov. Charles S. Robb at a Jefferson-Jackson Day dinner here the "with your money and my good looks" the Democratic Party can reach "new dimensions of accomplishment" in the 1980s.

Rockefeller last year spent a record-shattering $11.5 million, nearly all of which was his own money, in becoming the first Democrat in West Virginia history to be reelected governor.

The 1,000 Virginia Democrats who paid $125 each for tonight's dinner heard Robb finance chairman Alson Smith describe a big-for-them but modest-for-Rockefeller war chest for this year's campaign. "Our coffers are swelling. We already have over half a million," Smith said.

Robb joked that "some people ask me why I am running for governor this year. They say 'we just elected Jay Rockefeller last year.' Jay just missed being elected in four neighboring states and the District of Columbia."

Robb, who faces an equally well financed opponent in Republican Attorney General C. Marshall Coleman thanked Rockefeller "for the boost you gave our economy" by advertising on Virginia television and announced that he would "reciprocate this fall" by advertising on a TV station in Bluefield, W. Va.

Rockefeller said Democrats must follow the lead of Republicans and "develop a national strategy for research, direct mail and telephone support . . . and make effective use of advertising, and be unafraid of this."

The Democratic Rockefeller said the Republicans conducted a massive but "largely negative" television campaign nationally in sweeping elections last year. "Was it right is a value judgment, but it worked," Rockefeller said. "To be right is nice, but to be persuasive is to win."