Hard to say. You can't easily change people.

I guess it can come down to reputation a bit - have you been successful in other areas in your life that make people think you know what you're talking about?

Even then it's a hard sell at this stage, as I think many of the people who use Facebook the most are the least 'bright' - and it takes a little more brain power to use Steem / eSteem. Even Reddit is too complicated for many Facebook users.

Another challenge is that Facebook is heavily centred on being a platform to communicate with those you know - your friends. While this is also present in Steem, it's not its primary focus.

On the other hand, you can mention MySpace. Sites don't stay on top for ever.

Maybe just link to successful Steem posts on your Facebook account.