An important part of your website ranking with search engines is that other websites find your content interesting and display a link to your website.
Here you find a list of websites that are happy to exchange a link with you. You can utilise it to your liking.
Also, collaborate with other websites that might be relevant to your content like suppliers, customers etc. Ask them if they would put a link to your website on their website. You might reciprocate the favour for them.
There might be a lot more exchange websites, some of them might charge a fee. Simply Google "link exchange" to see what is available.
The list below are free exchange sites:
Travel Link Exchange Directory
Free link exchange and link building service for travel themed websites.
The Link Exchange - Your ultimate resource for link exchange!