Dear mate,
Build backlinks to your site from high authority site.
If possible try to get links from GOV, EDE domains. make sure your content is trustworthy to those site which is linking to you.
Always prefer to relevant niche site for building baclinks. Before going to above methods make sure your internal links are maintained with proper structure.
LIS is just a metrics given by third party. It will not considered by search engines..
Good Luck