1. Content relevance and depth
The single biggest ranking factor for most pages is whether the content is genuinely the best answer for the query. "Best" means: comprehensively covers the subtopics real searchers care about, cites authoritative sources, includes the unique data, examples, or perspective only you can offer, and is structured for easy scanning.
Word count is a weak proxy for depth — long thin content ranks worse than tight comprehensive content. Aim to be the most useful page on the topic, regardless of length.