There are many learned sages, philosophers and transcendentalists who try to conquer the senses, but in spite of their endeavors, even the greatest of them sometimes fall victim to material sense enjoyment due to the agitated mind. Even Viśvāmitra, a great sage and perfect yogī, was misled by Menakā into sex enjoyment, although the yogī was endeavoring for sense control with severe types of penance and yoga practice. And, of course, there are so many similar instances in the history of the world. Therefore, it is very difficult to control the mind and senses without being fully Kṛṣṇa conscious. Without engaging the mind in Kṛṣṇa, one cannot cease such material engagements.
(Bhagavad-Gita-------2:60-------purport).

Just by treating the root cause of an ailment, one can conquer all bodily pains and sufferings. Similarly, if one is devoted and faithful to the spiritual master, he can conquer the influence of sattva-guṇa, rajo-guṇa and tamo-guṇa very easily. Yogīs and jñānīs practice in many ways to conquer the senses, but the bhakta immediately attains the mercy of the Supreme Personality of Godhead through the mercy of the spiritual master. Yasya prasādād bhagavat-prasādo . If the spiritual master is favorably inclined, one naturally receives the mercy of the Supreme Lord, and by the mercy of the Supreme Lord one immediately becomes transcendental, conquering all the influences of sattva-guṇa, rajo-guṇa and tamo-guṇa within this material world.
(Srimad Bhagavatam------7:15:25--------purport).

Lord Kṛṣṇa told King Yudhiṣṭhira that He is conquered by the love of one who has conquered his senses. One who has not conquered his senses cannot conquer the Supreme Personality of Godhead. This is the secret of devotional service. To conquer the senses means to engage them constantly in the service of the Lord. The specific qualification of all the Pāṇḍava brothers was that they always engaged their senses in the Lord’s service. One who thus engages his senses becomes purified, and with purified senses the devotee can actually render transcendental loving service to the Lord and conquer Him.
(Krsna Book).