@Korvalus - most preparations are based on assumptions that the different world would have the same laws of physics, and you would be able to use them to create useful technology.
I think Death Mage is the only work that explicitly states the laws of physics are so different, our Earth knowledge is not directly applicable. Most other worlds are just like our own, but magic works. So it's a reasonable assumption to make. Just be flexible and don't forget magic is a good substitute for electrical power.
Our world has a long history of inventions that are actually pretty easy to make, but it took people centuries or millenia to actually invent them. Ancient Greeks probably could have made printing press, for example. One aspect of the preparation is learning about this stuff.
Our world has a long history of refining people's intellectual prowess. Positional numerals, scientific method, tradition of experimentation, numerous puzzles and philosophical problems... If you're coming to a world that's different from ours, you want to bring that stuff with you - it'll help you figure out how the new world works. It took Death Mage a lot of experimentation to make food that moves nations.
Our world has a long history of rogues, entrepreneurs and visionaries. It might not seem as glorious as slaying demons or printing books on science, but you can change the world for the better, line your own pockets, and avoid many pitfalls if you learn from them.