Easiest way to lead to higher Spiritual peace is by doing zikr (dhikr). According to Maulana Shaikh Nazim, by calling Allah's (God) name, you can attain peace and beat your 'nafs'.
According to Wikipedia, Nafs is an Arabic word meaning self. In Sufi teachings, it means more of false ego. When Sufis talk about opposing Nafs, they mean Nafs Ammara, which talks about personal ego.
By just saying Allah's name, we are keeping it simple and avoid our egos contradicting anything. Simple and fast is the key to internal peace.