Shipping agency (vessels) bussines - secure linkbuilding

Hi guys,
I need one advice regarding link building for the shipping agency. To be honest I see that in this particular bizz there is not a lot competition, but I would like build some good links and to bring targeted keywords to the top of google search. In your opinion, what is the best way to do that ? Web 2 blogs, blog comments .. any other suggestions is more than welcome!
Thank you!

Outreach is a good place to start. Check for lining opportunities.

Honestly, services usually just use PBN.

Check the competitor backlinks profile, as the competition is less just replicate what they done.