What are the etiquette pertaining to Dua (supplication) and optimum time?

Question

In fact, a true believer never gives up supplicating to his Lord and imploring Him for guidance. Allah Ta’ala teaches us to call upon Him and seek His forgiveness all the time. Allah Ta’ala says in the Noble Qur’an: And when My servant questions thee concerning Me, then surely I am near. I answer the prayer of the supplicant when he crieth unto Me… (2:186). The etiquette and manners pertaining to making Dua are as follows: (1) Praising Allah Ta’ala and sending peace and salutations to His Prophet . (2) Admitting one’s sins and showing repentance. (3) During supplication, one should begin with himself. (4) Repeating ones supplication three times. (5) Asking Allah Ta’ala with firm will and seriousness. (6) Using short rich expressions in supplication. (7) Observing humbleness and humility during supplication. (8) The voice of the supplicant should be neither so loud nor so low. (9) The supplicant should end his supplication with saying “Aameen” meaning ‘O Allah! Accept my supplication.