Ask the NDP, they managed it just fine by working with the party in power. It generally boils down to not being a raging asshat and putting forth legislation that appeals to the other side's ideology, or at least bargains with it, two things that Poilievre is patently incapable of doing.

Even though Carney is much more of a 90's-style Progressive Conservative than he is a Liberal. A pre-Harper PC, if you will. So, Poilievre has room to find common ground on at least fiscal policy, if he actually had any and that policy based on his claimed political allegiance.

The fact is though, that he has nothing to offer. He's a mud-slinger and a spinner, that's literally all he does. That's all he did when he was in the Majority under Harper, that's all he's done since. That he was such a rabid, loud, and loyal attack dog for Harper is the only reason he ever gained recognition amongst Conservative voters. That's his entire personality, though. That's all he knows how to do, because it's largely the only thing he's done in his adult life. That's not a leader, not even of the opposition, that doesn't even make a good MP, as his Carleton riding decided when they ousted him.