Beyond that, avoid using all caps, too many exclamation marks, and hyperbolic phrases ("ACT NOW BEFORE TIME RUNS OUT!!!!"). Poorly formatted HTML in your emails can also hurt how they’re handled. Every spam filter is different, so an email might pass through one filter but get flagged by another. For more comprehensive info on how spam filters work and how to avoid them, check out this guide by MailChimp.
If links and looks are set, begin interacting with the page. Abandon it, adjust the window size, convert. Are error messages appearing when they’re supposed to (if, for example, you don’t input all the form’s required info)? Is your CTA button working? If you abandon the page, are you retargeted with ads? When you resize the window, does your landing page respond accordingly?