most of the time, off-page SEO is synonym with backlinks. As long as you can get quality backlinks at a safe pace your off-page SEO worries are over.
As for strategy.... if your domain name is new (less than 1 year old) the strategy is to get 2-5 quality backlinks (PBN, guest posts, niche edits) per month for 2-3 months, then increase the number of backlinks to 5-10 per month for the next 2-3 months and so on until your site becomes old enough (2+ years old) and has lots of quality backlinks to rank almost instantly for any new article you add, and without needing a single backlink anymore.
If your domain name is aged (2+ years old, but preferably 3 or more) and you have already gotten 100s of quality backlinks to it in the past you can increase the number of backlinks you are getting to... I don't know... maybe 10-50 per month? But make sure they are quality (relevant to your niche and from established websites in Google, with daily organic traffic) and that you are building them steadily.
Of course, there is more to building backlinks that matter than this, and a professional backlinker will know how many backlinks he needs, how often, and where to direct them, but for newbies to SEO this strategy is pretty safe and rewarding. But it needs lots of money
