The primary weapon to be used by a Jew against opposition is Tefillah.

The path to merit the this Tefillah, which is the essence of vitality, is Shmiras ha'Bris.

Additionally a person has to understand the appropriate way to 'wield' this weapon of tefillah through mishpat, a middle, stable approach which is does not frame ones approach to Hashem in a biased way. Additionally giving tzedaka (also a bechina of Mishpat) before tefillah will also help one engage and keep his thoughts alligned.

One must engage in both Torah study and Tefillah, which strengthen allow each other to be realized in our approach towards engaging Hashem and realizing our potential.

One must not become discouraged if he does not see his prayers answered as (s)he thinks they should be; entitlement and expectation of reward takes away from our avodah.

Further, one must attach oneself to a tzaddik ha'dor to realize ones potential and have ones tefillos be fully effective.