What is the order of acts of worship, and which acts of worship yield the greatest reward?

Ibn al-Qayyim, in "Madarij al-Salikin," mentioned seven obstacles that Satan uses to tempt a person. These are: 1. The Obstacle of Disbelief (Kufr): Attempting to keep a person in a state of disbelief in Allah and His religion. 2. The Obstacle of Innovation (Bid'ah): If a person escapes disbelief, Satan strives to tempt them with innovations in belief or worship. 3. The Obstacle of Major Sins (Kaba'ir): After escaping innovation, Satan beautifies for them the committing of major sins. 4. The Obstacle of Minor Sins (Sagha'ir): If a person overcomes major sins, Satan trivializes minor sins for them, so they persist in them until they accumulate and destroy them. 5. The Obstacle of Permissible Matters (Mubahat): After overcoming minor sins, Satan distracts them with permissible matters, keeping them from increasing in acts of obedience and missing great rewards. 6. The Obstacle of Less Preferable Deeds (A'mal Marjuha): If a person escapes permissible matters, Satan commands them to perform less preferable deeds to distract them from what is better and of a higher rank with Allah. 7. The Obstacle of Unleashing His Soldiers: If a person escapes all of the above, Satan unleashes upon them the harm of his human followers through hand, tongue, and heart. This is inescapable for anyone who remains upright and calls to Allah.

As for the order of acts of worship and the best among them, it varies according to individuals and circumstances. However, the most beneficial thing for a servant is to constantly remember Allah the Almighty.