>>501>Is it the number of frames? more frames basically means more drawings which should translate to smoother motion. however we have to take into consideration the action itself. compare for instance the way characters run in Pucca to the way characters run in the Looney Toons and that to the way characters run in Ghibli films. you could add 8 billion frames into pucca running and ghibli key-frames alone will look more fluid simply because the animation itself has more actions.
>The way you arrange them(The perfect timing and techniques)?not so sure what you are asking here.
>The action in itself?not necessarily since the same action can be done in a lot of different ways, some will look good and some bad.
i would say is a combination of everything but lets not forget that animation is basically moving pictures. if your drawing looks bad and isnt consistent the illusion of movement is broken and the animation looks bad.
also did you mean animation as a whole or the one on the gif you posted?