We must try our best to obey them as much as possible as long as they are telling us to do something good and permissable. We must be gentle towards them and never even say "uff" to them.
Abu al-Faraj Ibn Al-Jawzî (d. 1201CE) explained:
To be kind to one's parents is: to obey them when they order you to do something, unless it is something which Allah has forbidden; to give priority to their orders over voluntary acts of worship; to abstain from that which they forbid you to do; to provide for them; to serve them; to approach them with gentle humility and mercy; not to raise your voice in front of them; nor to fix your glance on them; nor to call them by their names; and to be patient with them. (Ibn al-Jawzî, Birr al-Wâlidayn)
We must respect and honour them at all times regardless of how they treat us even if they oppress us. We must try to look for every excuse, opportunity and chance to serve them and make them the happiest. For us to never look at serving them as a burden but a great blessing.
Shaykh Ibrahîm Ibn Sâlih Al-Mahmud writes:
Treat your mother with the best companionship, then your father; because paradise is under the mother's feet. Never disobey your parents, nor make them angry, otherwise you will live a miserable life in this world and the hereafter, and your children will treat you likewise. Ask your parents gently if you need something. Always thank them if they give it to you, and excuse them if they do not, and never insist on a matter if they refuse to give you something. (Al-Mahmoud, How to be kind to your Parents, p.40)
We should try our best to speak to our parents in a soft voice. Muhammad Ibn Sirîn (d. 729CE) used to speak to his mother in a very soft voice, out of respect for her. He was also often seen in the company of his mother and looking after her. (Ibn al-Jawzî, Birr al-Wâlidayn)
We should make the best of every opportunity we have to treat our parents the best whilst they are still alive for we will be in utter regret when we realise how much reward we have missed out on not serving or treating our parents how we should have.
May Allah enable us to treat our parents they way they should be treated. Ameen