While all Torah and prayer is powerful, there is a special power of Mishnayot and Tehillim. Mishnyaot are said to clear impurities in the brain. Regarding Tehillim, the Ball Shem Tov said that if we knew the power of Tehillim and the effect in has in this world and Heaven, we would never stop saying Tehillim.
We will pray and learn Mishnayot or say Tehillim for the memory of your beloved ones or for your own success. You can choose one chapter, one masechet or the whole book.