Firstly you need to optimize your On-Page SEO means putting proper keyword, internal linking, meta title, meta tag, image alt tag, etc. If you are done with all these then create high-quality backlinks for your website. There are various off-page seo technique that you can utilize to create high-quality backlinks like Guest Posting, Article Submission, Forum Posting, Blog Comments, etc.
You can also use social media sites to promote your website.