Antarmukha and Bahirmukha Vrittis
You will get Antarmukha-Vritti (inward-moving mind) only after you have destroyed all the externalising powers of the mind. The Antarmukha-Vritti is the indrawing energy of the mind owing to increase in Sattva.
You must learn the art of making the mind introspective or turned inward upon itself through the Yogic Kriya, Pratyahara (abstraction). Those who know this practice can really be peaceful. They only can be really peaceful. They only can be really happy. Mind cannot do any havoc now. The mind cannot externalise itself. It can be kept inside in the Hridaya Guha (cave of the heart). You must starve the mind by Vairagya and Tyaga (renunciation of desires, objects and egoism).
When the outgoing tendencies of the mind are arrested, when the mind is restrained within the heart, when all its attention is turned on itself alone, that condition is Antarmukha-Vritti. The Sadhaka can do a lot of Sadhana when he has this inward Vritti. Vairagya and introspection help a lot in the attainment of this mental state.
The Bahirmukha-Vritti is the outgoing tendency of the mind due to Rajas. Further, on account of force of habit the ears and eyes at once run towards sound. Objects and desires are externalising forces. A Rajasic man full of desires can never dream of an inner spiritual life with Antarmukha-Vritti. He is absolutely unfit for the practice of introspection.
When the vision is turned outwards the rush of fleeting events engages the mind. The outgoing energies of the mind begin to play.
When you are firmly established in the idea that the world is unreal, Vikshepa (through names and forms) and Sphurana of Sankalpas (thoughts) will slowly vanish. Repeat constantly the formulae: "Brahman alone is real. World is unreal. Jiva is identical with Brahman." You will gain immense strength and peace of mind through the repetition.