Rav Yaakov Meir Schechter shlita writes on the topic of tefillah (Sefer V'Nichtav B'Sefer, Chelek 2, page 248):
"If one has a lowly spirit, his prayers will not be rejected (see Sanhedrin 43B). Perhaps, this is the meaning behind Chazal's statement (Brachos 10B): 'One should not stand in a high place and pray; rather, one should stand in a low place and pray.' When one considers himself lowly, he knows well that he doesn't deserve anything and that everything he receives is a result of Hashem's desire. Therefore, he prays properly. He begs Hashem for a free gift, even though he is unworthy and deserves nothing. A prayer like this is greatly valued by Hashem and can lead to great salvations. And even when one merits a salvation, he will know that it comes from Hashem and he will thank and praise him, and such a person is worthy of receiving his salvation."
