Always the first strategy is content, You should make unique and informative content. Other websites will automatically want to link your website.
Tip 2:
The second is Social Media. Share your post on social media pages and groups, where people need information related to your content.
Tip 3:
Third is Guest Blogging, You can submit a guest post to other blogs related to your niche. It is the most effective way to build backlinks.
Tip 4:
Fourth is Commenting and Discussion. You can comment on blogs and discuss topics on forums. Give your link to your discussion, Only on related niche.
Tip 5:
Fifth is Creating resources. You can create infographics, ebooks, and whitepapers and add your link to them. Also, other People will link to your resources in your blog.