There are many ways of doing this. The main one is to go where pokemon appear, like tall grass and caves, and battle wild pokemon. If you want to raise them quicker, then wait until the grass rustles, and there is a high chance of Audino appearing, who gives you much more exp. points. Or you can give them to the old lady in the building on Route 3 and she will raise them for you. Your pokemon will slowly, but surely, level up!
Anywhere, it doesn't matter.
well, it depends. If you train it well, that pokemon wuill bethe best in your pokemon world.BUT I highly suggest you train black kyurem because its stronger than white kyurem.
Victory Road.
Train it to level 40.
Nimbasa city, you need to ride the battle train.
victory road
you need to train very very hard with it
I don't know what you mean by that but you can find rare candies somewhere ? I guess ...
You just have to train your pokemon. I did and defeated him with no problem. Mainly with Reshiram and Focus Blast.
Either train your pokemon, or start over, or nothing.
if u mean black and white then just find audino's in shaking grass
train... train...TRAIN...