My master [the Arizal] told that the primary way to attain ruach hakodesh is to be cautious with brikas hanehenin (blessings over food) and to say these brachos with kavanah… By reciting the berachos with kavanah one removes the tumah from the food, it purifies his body, and he becomes pure and enabled to receive holiness.  The Arizal instructed us often on this matter. ~ R’ Chaim Vital zt”l