Guest posting is the most valuable strategy in SEO sector to get a backlink. But most of SEO experts are not careful about getting backlinks from targeted blogs. I will search high quality blogs related to your niche and outreach them to allow a guest posting opportunity on behalf of you. And they are going to allow a backlink in the article. I use paid tools to check the website metrics and make sure it's the perfect one for my client to approach. Mostly I use ahrefs to research blogs and choose the perfect one regarding your niche.