This is how I gained my first 80 fans in just a few days in 2016. But I also had a good start. Firstly, I have been on Facebook since the beginning of 2008 - so you can imagine that I already had a lot of friends. Of course, they are not my friends in the classic sense of the word, although I am friends with all of them.
Now maybe you haven't been on Facebook for long and don't have that many friends, what then?
This is a simple and very effective method. If you become active in groups in which your target group is active, you will quickly gain many new friends. You can then (a little later, this requires a little tact) ask them to like your page.
Many people behave in groups like chile telegram screening an elephant wrapped in bubble wrap with a tin drum full of marbles, skating on a slate board and bumping into everyone instead of quietly looking around first. But it's actually quite simple:
follow group rules
Almost every group has strict rules about what is allowed and what is not. In addition to link and advertising bans, which you should strictly observe, there are sometimes other rules that I also recommend you follow. In some groups (including my Marketing Magic group ) you are only allowed to present your blog posts in a special post once a week.
It should also be clear that you don't crudely poach members or customers from the group moderator(s). That is a matter of decency and politeness alone. That is what you would think, but it is often ignored. If you are in doubt about whether you are allowed to post something, just ask the group admin via PM whether you are allowed to post this or that. There is usually a way around it. And if not, you shouldn't be angry either.