It's be good to know what difficulty level you're playing at. But, my build for Korea for a science victory is basically this: Start with 2 scouts in the capital, send them out to explore, but do it manually. You are far better at deciding where to explore than the automation ai is.
After you have your two scouts, your best options will probably be a monument, a granary, or a worker, depending on what your start looks like. If you have multiple bananas/wheat/deer, you probably want to go granary.
As far as techs are concerned, my basic rules go like this:
Usually pottery first, then Luxury techs (so if you have spices nearby, get calendar, if you have salt, get mining, etc.)
After that, writing, then usually I grab 3 or four more ancient eras techs, then go for Philosophy.
After philosophy, education is king for a science victory, from there, I usually go towards scientific theory, then plastics, then rocketry, stealing tech to backfill. After rocketry, it's just going for the rocket techs.
Social policies: I like tradition. I start with the opener, then legalism, landed elite, monarchy, aristocracy, then oligarchy. Then I move over to patronage, hit the opener and consulates. After those 8 SPs, you should be into the renaissance age, so you can go into rationalism (absolutely necessary for science vic) After the opener, secularism usually pops your science up the most.
Other important things:
1) Never automate anything, workers, scouts, anything.
2) National college is a huge bonus, the sooner you can get it up, the better. That's why philosophy is so important. I usually get it up with 2-3 cities
3) I like to save oxford until I get rockets, then pop it for satellites. Grab hubble right away.
4) As a general rule, settle your great scientists into academies until you have plastics, then pop them for one time science boosts.
