What helps to make sci-fi or a fantasy book enjoyed by people who don't usually enjoy it?

I'll get it out of the way now and say that I'm not looking for the typical answers, such as making it a 'speculation fiction' (Brave New World, 1984, We, Handmaid's Tale, etc) or a YA themed book (Hunger Games, Twilight, etc.) So I'm wondering, with those things in mind, is it possible? What would it take? I am aware that there is a lot of people that flat out don't enjoy those genres because they are not believable. So would it only work if people can really relate to the conflict, setting, characters, themes etc. ? These genres are often considered 'nerdy' and I would like to hear if you think that a Sci-fi or Fantasy book be almost universally liked by anyone. Thanks in advance!