What is the correct method of praying Tahajjud prayers ?
Re: Tahajjud prayer
*usually people do two rak'at at a time for a maximum of 28 rak'ats. they also usually recite longer suras. *
Re: Tahajjud prayer
Peace NaMaan,
Offer Tahajjud prayer at third part of any night in shape of two rakats. You can offer as many time you would like. Our Prophet Muhammad 
offered Tahajjud prayers by many ways. See the second quoted hadith how He offered.
**In book ‘Prayer at Night (Tahajjud)’ of Sahih Bukhari hadith No. 221 & 236.
** Narrated Ibn Abbas: When the Prophet got up at night to offer the Tahajjud prayer, he used to say: Allahumma lakal-hamd. Anta qaiyimus-samawati wal-ard wa man fihinna. Walakal-hamd, Laka mulkus-samawati wal-ard wa man fihinna. Walakal-hamd, anta nurus-samawati wal-ard. Walakalhamd, anta-l-haq wa wa’duka-l-haq, wa liqa’uka Haq, wa qualuka Haq, wal-jannatu Han wan-naru Haq wannabiyuna Haq. Wa Muhammadun, sallal-lahu’alaihi wasallam, Haq, was-sa’atu Haq. Allahumma aslamtu Laka wabika amantu, wa 'Alaika tawakkaltu, wa ilaika anabtu wa bika khasamtu, wa ilaika hakamtu faghfir li ma qaddamtu wama akh-khartu wama as-rartu wama’a lantu, anta-l-muqaddim wa anta-l-mu akh-khir, la ilaha illa anta (or la ilaha ghairuka). (O Allah! All the praises are for you, You are the Holder of the Heavens and the Earth, And whatever is in them. All the praises are for You; You have the possession of the Heavens and the Earth And whatever is in them. All the praises are for You; You are the Light of the Heavens and the Earth And all the praises are for You; You are the King of the Heavens and the Earth; And all the praises are for You; You are the Truth and Your Promise is the truth, And to meet You is true, Your Word is the truth And Paradise is true And Hell is true And all the Prophets (Peace be upon them) are true; And Muhammad is true, And the Day of Resurrection is true. O Allah ! I surrender (my will) to You; I believe in You and depend on You. And repent to You, And with Your help I argue (with my opponents, the non-believers) And I take You as a judge (to judge between us). Please forgive me my previous And future sins; And whatever I concealed or revealed And You are the One who make (some people) forward And (some) backward. There is none to be worshipped but you . Sufyan said that 'Abdul Karim Abu Umaiya added to the above, ‘Wala haula Wala quwata illa billah’ (There is neither might nor power except with Allah).
Narrated Abu-Wa il: 'Abdullah said, “One night I offered the Tahajjud prayer with the Prophet and he kept on standing till an ill-thought came to me.” We said, “What was the ill-thought?” He said, “It was to sit down and leave the Prophet (standing).”
Re: Tahajjud prayer
JazaKAllah brothers