First and foremost, thanks to the company’s commitment to SEO, Tripadvisor always ranks high in travel related searches, which is half the battle. The business model also feeds the SEO effort, with the constant addition of new reviews adding to the searchable content.

But the company has a few more growth hacks up its sleeve. Some of these are brilliantly simple but effective. For instance, Tripadvisor encourages hotels to publicise good reviews by displaying badges. This is good for the hotels in question, but the badges also link traffic back to Tripadvisor and make Google rank that hotels reviews higher in their own search results. Here is a list with one of the most important ranking factors:

1. Keyword appears in top level domain
2. Keyword as first word in domain
3. Keyword in Subdomain name
4. Public vs. Private WhoIs -Private WhoIs information may be a sign of “something to hide”
5. Keyword in Title Tag
6. Title Tag Starts with Keyword: According to Moz data, title tags that starts with a keyword tend to perform better than title tags with the keyword towards the end of the tag:
7. Keyword in Description Tag: Another relevancy signal. Not especially important now, but still makes a difference.
8. Keyword Appears in H1 Tag
9. Keyword is Most Frequently Used Phrase in Document
10. Content Length: Content with more words can cover a wider breadth and are likely preferred to shorter superficial articles.

etc.

–> https://backlinko.com/google-ranking-factors

More to read:
https://claytonjohnson.com/optimize-seo