Taubah and Repentance

Q: I have a question regarding the hereafter. I currently know that I made mistakes in my past where I've eavesdropped and seen in other people's houses in the past. I don't ever intend to do it again but I have no idea on how to contact all the people that I have done this to. (It's impossible for me to find some random people). How can I resolve this issue and does Allah forgive major sins on the day of qiyamah and can he forgive my sin on that day when it comes to doing wrong to others like my self. I have a bad feeling that I'm going to get punished indefinitely and I all I want to do is resolve this issue.

Q: I am in a lot of trouble. My son was 21 years old. He is unmarried and he did a big mistake with a foreign girl. My son did sex for the first time. It is a big gunnah. Please give me a solution to have forgiveness from Allah Ta'ala.

Q:

1. How do you make repentance?
2. hat do you say to Allah when you repent? Say this will be enough? "Allah for give all of my sins"?
3. Do you need to raise your hands like do in dua?

Q: For repentance you need to feel guilty about the sin you committed. I don't feel guilty in my heart, can I verbally say that I feel guilty about the sin, would that be enough? I can say verbally "I regret doing the sin, I shouldn't have done the sin" would that be enough?

Q: If committed a sin, how many times you have to repent? I mean how many times you need ask forgiveness from Allah for a sin? Is once enough?

Q: If you want to repent for major sins you, do you need to pray salaah to get your repentance accepted or without salaah you repentance will get accepted? For example I want to repent for lying and drinking alcohol, do I need to pray salaah in order for my repentance to get accepted. Does repentance on it's own get accepted?

Q: A brother used to rape his own minor sister for many years. Later this same siter kills her brother, will she be accountable in the court of Allah?

Q: I had a question regarding committing a sin. If a person does one bad deed then he get one sin but example what if he is doing a sin which is a continuous sin example he is involved in interest or he doesn't keep a beard so is there something like he is getting a sin every second that passes untill he comes out of that sin?

Q: I did something bad and have made sincere tawbah. As of right now, I have not repeated it. I was wondering if there is anything I can do (dua' or action or anything else...) to make Allah conceal this mistake so as to protect me from the embarrassment and humiliation of it being exposed? Please give me sincere advice and make dua' for me.

Q: I had a question regarding tawbah. Can you give me a basic explanation on what are the requirements for one's tawbah to be accepted?