OTTAWA -- Boost defence spending, dial down the volume on battling climate change and find a bridge or energy project to build together.

That was the expert advice Prime Minister Justin Trudeau received Friday on how to get along with new U.S. President Donald Trump and make Canada relevant to his "America First" policy.

Derek Burney, a former Canadian ambassador to the U.S. under Brian Mulroney, said Trump's protectionist, pro-American inauguration speech need not be cause for the Trudeau government light its "hair on fire" because there is plenty of policy space for Canada to plug into.

"If physical security and economic growth are his priorities, we're in good shape to be constructively co-operative with him on both," said Burney.

"We have common infrastructure that needs modernizing along our border." He suggested joining forces to modernize the Canada-U.S. electricity grid, or jointly building the proposed Gordie Howe Bridge between southern Ontario and Michigan.

Boosting defence spending should also be seriously considered, said Burney because the U.S. is spending a disproportionate amount in NATO -- something Trump has complained loudly about this past week.

Roland Paris, Trudeau's former foreign policy adviser, said increasing defence spending makes sense regardless of Trump, because it's a necessary "insurance policy" in an unstable world beset with security threats.

"The 'America First' model that Trump has articulated poses a signal challenge to all of America's partners, whether it's Europe partners, other members of NATO, Mexico, Canada."

Canada doesn't need to be scared of the Trump administration as long as it creates "a relationship where they see us as partners, not competition," said Georganne Burke, an American-born Trump supporter who is a vice-president of a Toronto public relations firm.

But Trudeau and his ministers have to hold firm to their constructive approach towards wanting to find common ground with Trump and "stay away from the snark" in its messaging, she said.

That means toning down the rhetoric on the threats posed by climate change because most U.S. conservatives were angered by Barack Obama's characterization of it as the greatest threat to the world, she said. "They will be willing to talk about environmental issues but they're going to talk about it in a more conservative fashion."

Colin Robertson, a veteran ex-diplomat with extensive U.S. experience, said it is crucial for Trudeau and his team to continue pushing the fact that millions of American jobs depend on trade with Canada and that 35 U.S. states count Canada as their top customer.

Robertson said Trudeau took the right approach when said he looked forward to working not only with Trump's administration but with Congress, state and local governments "to restore prosperity to the middle class on both sides of the border and to create a safer and more peaceful world."

Trudeau reminded Trump of Canada's historically close ties with the U.S. in his congratulatory statement issued minutes after the billionaire businessman was sworn in as the 45th president.

"This enduring partnership is essential to our shared prosperity and security," Trudeau said, citing "robust" trade, investment and economic ties that have long linked the two countries, while supporting millions of jobs.

"We both want to build economies where the middle class, and those working hard to join it, have a fair shot at success."

Trudeau also spoke to the provincial and territorial premiers about the new administration.

His office said he and the premiers stressed the importance of the Canada-U.S. relationship and discussed the opportunities presented by the transition in Washington.

Earlier Friday, the prime minister urged the mayors of Canada's biggest cities to keep close ties with their American counterparts to maintain an open border with the U.S. Those relationships will be vital to ensuring open dialogue and trade between the two countries, he said.

The mayors say their relationships with municipal leaders on the other side could serve as a counterbalance to any protectionist movements initiated by the Trump administration, given the trade ties between Canada and American cities and states.

"The United States is not just one president," said Montreal Mayor Denis Coderre, who pointed to an upcoming meeting he has with Chicago Mayor Rahm Emanuel on the issue of climate change.

"It's a complex system and we'll do what we have to do. We are already working really hard with different colleagues from south of the border."

Calgary Mayor Naheed Nenshi said he hopes Canada remains open to immigrants from all over the world should Trump follow through on his protectionist threats.

"Let's ensure that we are open to the world, to trade, to brains to money to ideas and make sure that we seize on this opportunity."

Toronto Mayor John Tory said taking a seat in the Oval Office could change Trump.

"You realize you have to represent and lead everyone. So I'm hopeful that President Trump will understand that with that office."