He's right, as obvious as the advice sounds. Poilievre blew what should have been an easy win because (in part) he only talked to people who already supported him.
The NDP in Ontario has been in Opposition for years now because Doug Ford is good at winning elections. He's a dreadful premier, but he's an excellent retail politician.
Once you start winning you have a record you can point to and that helps you build momentum to win again.