The infamous "fold"
There's still a debate going on in the web development community about the importance of the "fold" (first visible part of a website).
In a 2015 study, Amy Schade from the Nielsen Norman Group concluded that "the fold still exists and still applies" and that "the 100 pixels just above the fold were viewed 102% more than the 100 pixels just below the fold" (“The Fold Manifesto”).
So, that being said, the unofficial McGill point of view on this aspect (for now) is this:
“Focus the initial screen and let those users who're particularly interested dig into the rest” (Nielsen & Budiu, 2013, p. 120).
Optimize positioning
While we let people debate about the "fold" issue, let's talk about positioning. It's really important to prioritize and position your content so that people see it.
“Generally users look for high-priority information in the upper left of the content area” (Nielsen & Pernice, 2009, p. 97)
And here's how it looks in a more easy to understand image:
Can't see this image? Here's a text version.
References
Mobile usability by Jakob Nielsen and Raluca Budiu
Eyetracking Web Usability by Jakob Nielsen and Kara Pernice