Witr and Nawaafil

Q: What is the correct way to perform tahajjud salaah? 

Q: If a person starts reading the four rakat sunnah before the jumaah khutba azan, and azan begins, what do i do? Make it 2 rakats, or read all four rakats? If I start my sunnah before the azan of the khutba, and know that I can finish the full four rakats before the azan ends, can I perform the four rakats?

Q: Can you give the proof and hadith in which the prophet (Sallallahu Alayhi Wasallam) prayed four rakaats sunnah at once. Someone is saying that the prophet (Sallallahu Alayhi Wasallam) prayed them 2 then 2 so can you give the hadith and its strength?

Q: When I reached masjid for tarawih, four rakath already finished, then I prayed first four rakath Isha and started for tarawih. When I started to pray for tarawih seven rakath is going on, after finishing tarawih by imam, still I need perform 6 rakath tarawih. In this situation what I need to do, whether I need to pray witr salaa to follow by imam with jamat first and then need to perform balance six rakath tarawih, or first I need to perform balance six rakath tarawih and perform witr salaah alone?

Q: Great virtues are mentioned in the Ahadith for praying 4 rakaats after Zuhr and Isha.

Should one perform these apart from the confirmed 2 rakaats sunnah that are prayed after Zuhr and Isha i.e. first 2 rakaats and then 4 rakaats? And these 4 rakaats should they be prayed with one taslim or 2 by 2 rakaats?

Q: Praying four rakaats after the fard of salaat Esha is mentioned in Ahaadith. Its mentioned that the virtue is that one will gain reward as having prayed these four rakaats on Laylat al Qadr. There are both Marfu and Mawquf reports regarding this. Should this be prayed after the 2 rakat sunnah muakkadah as adding 2 rakaats seperately or adding 4 rakaats either seperately or in two sets? 

I read in Qutul al Quluub that Ibn Masud (RA) did not like to pray after the Fard a same amount of Nafila rakaats, they would pray Isha and thereafter 2 rakaats and thereafter 4 rakaats. Is this true?

In Musannaf Ibn Abi Shayba 2/206 there is a report from Umar (RA) that he did not like to pray after Jumuah the same amount of nafil i.e. 2 rakaat. What Ibn Masud (RA) would do, is that 2 rakaats and thereafter 4 rakaats with one taslim?

Q: Is there a limit of how many rakaats of nafl a person can pray with one salam example is it permissible to pray 12 rakaats of nafl with one salam? 

Q: A person who prays two rakaats with the intention of tahajjud prayer after Isha salat, will he get reward of praying tahajjud?

Q: What is the status of taraaweeh salaah that is performed in the month of Ramadhaan?

Q: Which sunnat salaah if left out will it be sinful?