>>714733679For hitting the same note several times in a row, it's usually easier to have two buttons for it so you can just alternate, though in some situations when you get better and faster, it can be easier to hit the same button again. Some of that is just being warmed up, used to the buttons, and gaining experience.
As far as hitting multiple notes at once, take note of the shape. For the most part, you can tell which two or three they are just by how they're spread on the screen or how the combo is shaped, though in the really hard songs you have to fully read them. On Normal, iirc, it will give another prompt on screen as to which buttons to hit for it.
Ah, good. On controller, putting all 4 on both triggers is good for being able to pass a hold on when adding more notes to it. I've heard that putting the two opposite notes on bumpers can be useful for ease of thought and to be able to just hit the applicable bumper and then face button for 3 at once.