Police and protesters have been clashing in Ferguson, Mo., since the shooting death of teen Michael Brown on August 9.

Toronto's police force faced angry protesters when the city hosted the G20 political summit, and some of the lessons they learned could be applied in Ferguson.

When anti-G20 protesters started rioting in Toronto, police used tear gas in the city for the first time.

An after-action report later revealed that "displays of real or implied force can lead to negative crowd reactions that may escalate a situation."

Steven Summerville, a former police trainer, agrees.

"You don't wish to create alarm. You don't wish to create anger or fear with your crowd," he said. Police need to "get out there" and lighten up on the uniform, he said.

Summerville recognizes the differences in the situation in Toronto during the G20 and the one currently in Ferguson.

In Toronto, protesters were angry with politicians, policies and ideals. In Ferguson, police are attempting to de-escalate an event where they are the source of scorn, he said.

But, their military-like tactics aren't helping, said Summerville. Instead, plain uniforms and bicycles would be preferred.

Recently, police tactics in Ferguson appear to be changing. Officers are starting to pick out alleged provocateurs, reports CBC's Steven D'Souza.

"Usually, it quells violence," said Summerville. "And it usually starts to prevent or create an environment where people can start to calm down."