RE: What is most important thing you want to achieve if you land in a different world?

realistically speaking?

1st scenario, getting dropped off into another world
-if it's in the wild, gather everything u can get for immediate survival, moving as fast as possible to civilization(s) in the proccess
-gather info. while try acting as normal with common senses depend on the level of that civilization as possible, try not to be an odd ball
-learn how to fight a little bit, try to learn a craft or some job and settle down
-invent something, or better yet, advise someone on inventing something and take % profit
-stay away from business, diplomatics, etc. as far as possible especially if it's about those invention that u directly, or indirectly introduce

2nd scenario, getting summoned
-don't try to be a righteous retard "o-hero", but don't try to go all-out against them, like all those o'-i-am-so-smart MCs in fictions
-instead, keep ur head low, gather anything they can offer u, training, knowledge, funding, temporarily acting good-puppy to benefit yourself 1st
-if possible, strike a deal, as safe, with as few holes as possible, create some holes in the deal for yourself to sneak through
-don't try to show off your preparedness and "smartness", always try to act a little bit dumb or naive to at least certain extends, the "smarter" u seem to be, the more possibility that they see u as a threat
-best scenario, get them the impression that u 're someone at least a little bit capable with the brain instead of muscles so u may strike a violentless deal with them and end up staying safely in the backline doing "paper works" and "engineering works", "researching works" instead of the frontline holding the sword
-since u 're in new world with no ally, try to make connection with one potential side, "enemy of enemy is ally"

3rd scenario, reincarnated
-rather good scenario, since u get a lot, really, a lot of time and choices to make preparations

RE: What is most important thing you want to achieve if you land in a different world?

The first thing should be to learn the rules of the world. In order to play, you must know the rules first!

After that, it's the pyramid of needs. It's the same in our world.
When basic needs are filled, you aim to fulfill higher needs.

At the lowest level you need food, shelter, water and air and to survive.
Then comes higher needs. Security, both physical and economical. Friends. Resources, like money.
After that even higher needs, like fullfillment and a reason to be.
After that you can aim to become a driving force in the new world. King, religious leader, maybe a god.