Idea generation is a skill you pick up with practice. You don't need a book for it. You basically just go around, thinking, "What if?" and applying it to everything. Some of the ideas will suck, others won't. With practice you'll have more ideas than you need, and you'll learn how to distinguish the good ones from the bad ones.
What if...everyone could teleport? *Everyone*? And they always had been able to? They were born with it? How would that affect a culture?
No roads. No cars. No domestication of horses for riding (there would be no point). The whole environment would change. The wheel wouldn't have been quite the same invention that it was for us. Stairs and ramps would not be necessary--just teleport to the second floor. No jails--criminals that we would jail would get some other sort of punishment. Cities would not be needed as much--people can just teleport to each others' homes and do their business that way. Perhaps there would be more crime--criminals could just vanish from the crime scene. Perhaps this would spur people running around in packs, so a group of criminals couldn't pop in and hurt them. Perhaps your home would be your biggest, darkest secret, so that other people who might hurt you can't get a mental image or something to teleport to. If the criminals don't know where you live, they can't teleport to get you. They'd have to walk, which would be a thing that's hard and difficult to do in this world of teleporting people, because there would be few roads through the wilds.
You could write an entire world on this premise, just by following the logic. Take out nearly everything we have in place that was discovered or made due to us needing a better mode of transporting than walking or running from place to place. Think about how much of our society is based on modes of travel--cities are on bodies of water because it makes it easier for boats, which are faster than walking, to come and go. When railroads came, railroad cities popped up along them.
New professions would be created--can these people teleport things they are holding? Sure, but what if it were only small things. Some people would be teleporting couriers. Perhaps there would be a few roads, for cargo, or perhaps all trade would be massively decentralized. What if teleporting a lot in a short amount of time was dangerous? Teleporting couriers would either by paid a lot, or they would be child labor, done by young and poor people who couldn't find better, safer work.
Ideas come from asking "What if?" and then filling the blanks with logical answers.
