3. a. Be in a state of purity, face the Qiblah, and raise your hands when making duas.According to Fiqh us Sunnah, volume 5, #96b, one must maintain a complete state of purity. face the direction of Ka’bah, seek forgiveness of Allah as much as possible. glorify Allah, and supplicate for one’s well being and welfare in this Iife and in the Hereafter, and for others, with fervor, attention, and with hands raised in supplication. Osamah bin Zaid reported: “I was riding behind the Prophet (peace be upon him) in Arafah, while he raised his hands in supplications to Allah.”
Source: Fiqh-us-Sunnah.
The Prophet went towards the Musalla and invoked Allah for rain. He faced the Qibla and wore his cloak inside out, and offered two Rakat.
Source: Abdullah bin Zaid in Sahih Bukhari, volume 2, hadith 125.

3.b Raise your hands in front of your face, but not above your head.Umayr saw the Prophet (peace be upon him) praying for rain at Ahjar az-Zayt near az-Zawra’, standing, making supplication, praying for rain and raising his hands in front of his face, but not lifting them above his head.
Source: Narrated Umayr, the client of AbulLahm, in Sunan Abu Dawood, hadith #450

3.c. Supplicate with the palms of your hand upward.The Prophet (s) said. “Supplicate Allah with the palms of your hands; do not supplicate Him with their backs upwards. When you finish supplication, wipe your faces with them.”
Source: Narrated Abdullah ibn Abbas in Sunan Abu Dawood, hadith #578.

3.d. Make Wudhu (ablution) before asking du’a[...]I returned and entered upon the Prophet at his house, and found him lying in a bed made of stalks of date-palm leaves knitted with ropes, and on it there was bedding. The strings of the bed had their traces over his back and sides. Then I told the Prophet about our and Abu Amir’s news and how he had said, “Tell him to ask for Allah’s Forgiveness for me.” The Prophet asked for water, performed wudhu and then raised hands, saying, “O Allah! Forgive
‘Ubaid, Abu Amir.”
Source: Narrated by Abu Musa in Sahih Bukhari, hadith 612.