There is a well known segula for one who needs a yeshua for anything (shidduch, health, parnasa, etc.) to daven at the Kosel Hamaravi for forty days in a row. Rav Moshe Shternbuch shlita of the Batatz Eidah Chareidas (descendant of the Vilna Gaon) says (Teshuvas VeHanhogos 4:61) that this could be done even if one doesn't have access to the Kosel. One can go to a any specific Shul or Beis Medrash for forty days straight to daven for a particular need and will have the same segula. He says that one should give 18 "prutos" tzedaka to those that toil in Torah before each of these 40 tefilos.