In Srimad Bhāgavataṃ 7.5.23-24, Prahlada says there are nine ways of worshipping the Lord. They are famously known as the Navavidha bhakti margas.
śravaṇaṁ kīrtanaṁ viṣṇoḥ
arcanaṁ vandanaṁ dāsyaṁ
iti puṁsārpitā viṣṇau
bhaktiś cen nava-lakṣaṇā
kriyeta bhagavaty addhā
tan manye ’dhītam uttamam
Translation : Prahlāda Mahārāja said: Hearing and chanting about the transcendental holy name, form, qualities, paraphernalia and pastimes of Lord Viṣṇu, remembering them, serving the lotus feet of the Lord, offering the Lord respectful worship with sixteen types of paraphernalia, offering prayers to the Lord, becoming His servant, considering the Lord one’s best friend, and surrendering everything unto Him (in other words, serving Him with the body, mind and words) — these nine processes are accepted as pure devotional service. One who has dedicated his life to the service of Viṣṇu through these nine methods should be understood to be the most learned person, for he has acquired complete knowledge.
The nine forms of devotion are:
- Shravanam – Hearing the names and glories of the Lord
- Keertanam – Chanting His glories
- Smaranam – Remembering the Lord
- Pāda sevanam – Serving the Lord’s feet
- Archanam – Worshiping the Lord
- Vandanam – Offering obeisance unto the Lord
- Dāsyaṃ – Serving the Lord as His servant
- Sakhyam – Developing friendship with the Lord
- ātma Nivedanaṃ – Total surrender of oneself to the Lord
Even though the paths are different, they all lead to the same destination.
But from the above list Dāsyaṃ, sakhyam, ātmanivedanaṃ are practically not possible for normal human beings like us. So, the best ways one can easily follow are :
Hearing the glories, songs, bhajans of the Lord whenever possible.
Singing or chanting the Lord's name and glories.
The easiest way possible. Remembering the name of the Lord whenever possible.
Prostrating before the lord. Offering obeisances to the Lord.
These are the easiest ways you can remember the Lord whatever you are doing.
Before having food, offering it to the Lord as gratitude also helps in developing devotion in one's heart. You can learn more about devotion from this answer.
In one statement: You can chant or remember the name of the Lord while you are performing any other daily life activity (say while you are in office or having lunch).