If you read many master books, a common theme you will find is that masters do not win games because they can calculate so many moves ahead. Rather, they eliminate the obviously poor choices based on a number of factors, leaving only a few to be considered.
At that point, you have what most you might call "candidate moves". In many cases, there are more than one that are fine, and the move chosen should be one that best suits your style.
Where the position warrants some calculation, instead of calculating "as deeply as you possibly can", I would focus on calculating as far as you need in order to reach a position you are comfortable with.It's unlikely that at club level play, calculating more than a few moves ahead except in very specific cases will be beneficial.
How do you improve your calcaluations? I've read in a book that you choose the 3 best choices that you think you can make and try to see a deep as you possiblely can. Is this to be true?