Headline capitalization rules from The Canadian Press Stylebook (17th) and updated info from The Canadian Style online are summarized in a chart in my Canadian, Eh? column at Copyediting.com today.
For more on capitalization in general, see this earlier article and this one from the Canadian standpoint. Also see the title capitalization website and Erin Brenner’s fantastic summary chart in this article—addressing styles from CMS16, AP2014, APA6, AMA10, Gregg11, Can1997, and Yahoo.