Hakim al Umma Mawlana Ashraf Ali Thanawi (Allah have mercy on him) said,

‘Even the Shaikh should not sit idle. He should keep progressing in excellence.
Allah says,

‘and say, “My Lord, improve me in knowledge.” ‘[20:114]

He should not make a claim of excellence. However, there is no problem in mentioning the blessings (of Allah bestowed on him).

Allah says,

‘So, do not claim purity (from faults) for your selves.’ [53:32]

And

‘And about the bounty of your Lord, do talk.’ [93:11]

He should be eager on spreading the tariqa
Allah says,

‘who is very anxious for your welfare, [9:128]

He should be very kind and loving with the disciples.
Allah says,
‘and for the believers he is very kind, very merciful.’ [9:128]

He should forgive their shortcomings and mistakes.
Allah says,
‘Had you been rough and hard-hearted, they would have dispersed from around you. So, pardon them, and seek Forgiveness for them.’ [3:159]

He should not ignore them for the the sake of (wealthy or famous) worldly individuals.
Allah says,
Do not expel those who call out to their Lord morning and evening seeking His pleasure. You are not responsible for anything in their account, and they are not responsible for anything in your account, that you should expel them, and thus become one of the unjust. [6:52]

He should not expect any worldly benefit from the disciples.
Allah says,

‘Keep yourself content with those who call their Lord morning and evening, seeking His pleasure, and let not your eyes overlook them, seeking the splendor of the worldly life. And do not obey the one whose heart We have made heedless of Our remembrance,’ [18:28]
And,
‘ I did not demand any reward from you. My reward is with none except Allah,’ [10:72]

He should remain patient on the afflictions caused by fellow men.
Prophet (Allah bless him and give him peace) said,
‘May Allah have mercy on my brother Musa, who was afflicted more than this (by his Umma) but he remained patient.’

He should maintain serenity and dignity. Otherwise disciple will consider him to be paltry and will not benefit from him (spiritually).
As is said regarding our Prophet (Allah bless him and give him peace) that whoever saw him from far away was intimated and whoever saw him from close by loved him.

He should not give preference to a disciple over others.
Allah says, ‘He (the Prophet) frowned and turned his face,’ [80:1]
However, if a disciple has more yearning of Allah(‘s pleasure) than it is fine to give preference to him.

He should not do anything that will make people have a bad opinion about him. As this will close the path (tareeq) of seeking instructions and benefiting (irshad).
Allah says,
‘the one who calls (people) towards Allah,’ [33:46]

Taleemud Deen, page 129-31