More often than not it doesn't matter, you cast a spell and it either lands in its designated spot on the field, or it resolves and heads into the graveyard.
What I always wondered is, whenever there is a complicated situation playing out in the stack, is there a specific place you are supposed to put your cards?
1) I play Storm Crow
2) My opponent casts Dissipate targeting Storm Crow
3) I play Negate targeting Dissipate
4) My opponent plays Cancel targeting Negate
5) I play Counterflux targeting Cancel
While all this is happening, is it 'acceptable' to simply lay the cards down on the play-space or for official, tournament-level play do I need to immediately place my cards in the graveyard and simply remember they are on the stack in their particular order?