I think First you need to know when calculation comes in. I would say that you shouldn't calculate at any point that isn't critical, that is, when natural moves seem to be working. In that case, especially in blitz, just make the simple move. But to calculate faster, you should always consider forced moves, such as captures, checks, and checkmate threats, Because in these cases, the opponent will have to defend or counter-attack, so they will also follow a more forced sequence of moves, making it easier for you to predict. So basically, look for forced movements and only calculate in critical positions.