Sajda-e-Sahw

Q: How many different ways can one perform sajdah sahw? I like to do 2 sujood and say salam after finishing whole namaz in normal way. Is this right?

Q: During a four rakat prayer, if one has forgotten whether they are in rakat two or three, and they decide two is more likely so they sit and read attahiyyat, do they also have to read tahiyyat after the next rakat, which they assume is the third one?

If one is not sure whether they are in rakat one or two, and they decide two is more likely so they sit and read attahiyyat, do they also have to read attahiyyat after the next rakat?

Q: If I forgot to sit in tashahud in the last rakaat of Asr Salah and stood up, what should I do now? 

Q: After every single namaaz can I do sajdah twice then make salaam and count it as sajdah sahw. I feel like my namaz isn't perfect that's why I do short sajdah sahw after every namaz.

Q: In almost every salah I tend to think that I skipped something that I need to do sajda sahw for, but I believe it is not correct everytime. No matter how much I tend to focus and not do sajda sahw, I think that I skipped this out or that. What is the ruling in such a case?

Q: I was performing two rakaats of salaah, and when I stood up for the second rakaat, I began reciting attahiyyaat by mistake. As soon as I realized, I stoped reciting attahiyyaat and started reciting Surah Faatihah. Is my salah valid?

Q: What should I do if I pray 3 rakaats instead of 4 rakaats mistakenly?

Q: If in salaah I did not recite a surah in the 3rd rakaat of the 4 Sunnah, do I make an extra rakaat as qadah?

Q: I made the intention in my heart to recite long surahs in fajr salaah, but I forgot and recited short surahs instead. Does this make sejdah sahw waajib?

Q: I did not sit for qa'dah in the third rakaat of Magrib and I went straight into a fourth rakaat. I completed the rakaat and then made Sajdah Sahw. I was a munfarid. What is the status of the salaah?