Link building is very important in SEO. I must say before diving into Link building efforts you should start with optimizing your content. Onpage optimization is super important, try to write on easy to rank keywords this brings you impression and clicks on your website.

First step for link building is to go for entity stacking, build Social link  Facebook, Twitter, Pinterest etc.

Start with entity stacking, go for free social profiles, then choose relevant directory submission always submit on high DA sites and once you do this then go for niche guest posting sites.