Question 6: How can players make the world seem real?
By taking what you have built for them and running away with it, by going left when they should have went right, and often by totally misunderstanding a verbal hint or random clue that sets them on a course you weren’t expecting.
I vaguely recall reading–as a teenager–the novel “Job: A Comedy of Justice” by Robert Heinlein, in which the hero character, Alex, is thrown through a series of ‘world changes’ implemented by Loki, acting with God’s permission.
There’s a moment when Alex realises that these aren’t whole worlds being created one-after-another all around him. Each world only exists as far as he can see, as far as he can readily interact–this hotel lobby, this street of shops, this cabin on a ship–the rest of it is emptiness and void, unformed.
So, the players make the world real by acting like that’s not the case. Acting like the entirety of this particular planet exists, and not just the shabby space-port and the three or four random staff you created just before the session started.
The world is real if the characters can see the farthest mountain and imagine they can walk there.