MANCHESTER, N.H. — Mitt Romney boasted an enviable advantage in the first-in-the-nation primary state when he launched his campaign for president: A governor of Massachusetts, he also owned a house on the shores of Lake Winnipesaukee. But as recently as February, Granite Staters appeared to harbor little interest in the boy next door. Polls had him lagging far behind John McCain and Rudy Giuliani.

In the last few months, however, Romney has steadily pushed to the head of the Republican pack in New Hampshire, while his major rivals have lost ground. A mid-July poll had him opening up a 15-point lead.

Romney has benefitted from larger forces shaping the race, notably, McCain's difficulties. But he has also run a campaign that might have been lifted straight out of "The Official Guide to Winning the New Hampshire Primary," if there were such a guide to the conventional wisdom. The formula: win over influential activists, advertise early, and lavish New Hampshire with attention.

"It's really no secret what Romney's been doing," said Fergus Cullen, chairman of the New Hampshire Republican State Committee, who is neutral in the race. "They have run the most traditional campaign in New Hampshire, characterized by the most visits here and the best grass-roots organization and by running a campaign aimed directly at likely Republican primary voters."

Summer polls rarely predict the winner of the election, however, and Romney's opponents say they have only just begun to fight in New Hampshire.

But with Romney's surge in the polls came a rise in expectations: With McCain seriously weakened and with Romney's early advantages in New Hampshire, it is hard at this point to see a state where he is better positioned to win.

Romney has made 65 stops during 23 official trips to New Hampshire since the last presidential election, according to the Globe's running count, more than McCain and Giuliani combined. Marketing himself as a business leader and family man with a Reaganesque optimism about the future, he has visited all 10 New Hampshire counties, headlining Republican fund-raisers, dropping by ice cream stands, and, more recently, holding town-hall-style forums where he invites locals to "Ask Mitt Anything."

He has had 14 full-time staff members on the ground for about two months, his campaign says, enough to make sure that every visit by the candidate is carefully planned and that Romney is represented whenever Republicans gather.