I joined the reading lists provided by Krishna.com which started recently. Every day I receive a five minute reading assignment of each of the Gita, Nectar of Devotion and Science of Self Realisation. They are short meditations. Very powerful but not overbearing.
Here’s a quote I picked up from the Introduction to the Nectar of Devotion which I really like. Prabhupāda basically tells us how to think of Kṛṣṇa.
*A Kṛṣṇa conscious person always thinks of the activities of the Lord—as He is speaking on the Battlefield of Kurukṣetra or engaging in His various pastimes in Vṛndāvana with His devotees. In this way one can always think of the activities and pastimes of the Lord. This is the mental culture of Kṛṣṇa consciousness.
[05. Other Books by Śrīla Prabhupāda / The Nectar of Devotion, “Bhakti-rasāmṛta-sindhu” / NoD Introduction]
Ok, so that’s really easy. Study the Bhagavad-gita and Kṛṣṇa’s Vṛndāvana pastimes in the tenth Canto of Śrīmad-Bhāgavatam.