Answer
The first level of surrender is external. If you are sincerely following the system given by Śrīla Prabhupāda and acting according to the directions received through the authorized disciplic succession, then you have already established the first level of purity and surrender.
The deeper question is whether, internally, your consciousness is fully surrendered. This is something that develops gradually.
To deepen surrender, one must continuously improve both the quality of one's sādhana and the quality of one's service.
As the quality of sādhana improves:
The quality of service improves.
The quality of surrender increases.
One becomes purified.
One receives transcendental knowledge.
When transcendental knowledge develops, everything becomes clearer, and one naturally acts in a surrendered mood.
Without transcendental knowledge, it is impossible to render completely pure, surrendered service. Such knowledge and realization arise from the combined practice of sincere sādhana and practical devotional service.
Sometimes devotees make the mistake of separating these two. They think that spiritual advancement is measured only by the amount of service they perform or by the visible results they produce.
That is not the proper criterion.
A devotee who is capable of accomplishing many things in the Lord's service must simultaneously ensure that the quality of his sādhana continues to improve. As sādhana deepens, the consciousness behind the service also becomes purified.
Producing results for Śrīla Prabhupāda's mission is certainly wonderful, but alongside that one must continue hearing, chanting, studying the scriptures, and cultivating proper consciousness.
One should constantly examine:
In what mood am I performing this service?
Who is actually producing the results?
Am I remembering that Kṛṣṇa is the real doer?
Am I remaining Kṛṣṇa conscious while rendering service?
This internal consciousness develops gradually.
If a person focuses only on producing external results, he may mistakenly conclude that he is making spiritual advancement. External success alone is not the measure of advancement.
It is true that when a devotee becomes purified, the Lord may increasingly use him as an instrument. However, the reverse is not necessarily true. Simply being used as an instrument for many activities does not automatically mean that one has become spiritually pure.
Even a neophyte devotee may possess many natural abilities and may be engaged in significant service by the Lord. But if he neglects his own purification, that service may not remain spiritually sustainable.
Without purification, many unwanted desires (anarthas) can gradually grow alongside successful service.
These include desires for:
Name and fame.
Personal success.
Prestige.
Control over others.
Exploitation.
Recognition.
Such tendencies are like weeds that grow in the heart alongside successful preaching.
These weeds can only be removed through sincere sādhana.
Therefore, both sādhana and service support one another. Neither should be neglected.
At the same time, one should not go to the opposite extreme by performing only personal sādhana while avoiding practical service.
A neophyte devotee requires practical engagement. Through devotional service, one gains realizations that deepen one's chanting and help remove unwanted material tendencies.
Śrīla Prabhupāda therefore gave a perfectly balanced process that combines direct association with the Lord through sādhana and practical association with the Lord through service.
Morning practices such as hearing, chanting, Deity worship, and worship of the spiritual master are direct association with the Lord.
Throughout the day, practical preaching and devotional service are also association with Kṛṣṇa. There is ultimately no difference between the Lord's holy name, form, activities, and service—they are all transcendental.
However, in our present conditioned state, we do not naturally experience service with the same realization as we experience formal sādhana. Therefore, we must gradually develop the quality of our service.
This is a lifelong process.
The quality of service depends not merely on what we do, but on the consciousness behind it—the knowledge, feelings, intentions, and understanding of whom we are serving, what pleases the Lord, and what the ultimate purpose of service is.