Unfortunately, the early moves in the game ("Joseki") are the most important. They are also the most difficult to learn. It is essential to study these tactics in this website... if only because they are the only "ground truth" known about Go. But for rapid improvement, the only real way forward is to play lots and lots of games to learn how the early game flows. Direction of play, which side of the board is most imp…
Nah, they aren't the most important (you can do without), not are the usual ones particularly difficult to learn.
Source: I'm a European 4 Dan.
(To expand on this: if you're a beginner, joseki don't matter. When you become a strong player (several of my friends are professional players), joseki is something you can usually come up with, or you come up with a similarly good non-joseki move, which is also ok. Practically, the game is usually decided in middle game fighting.)