Could you check my sentences?? please fix them to use in daily life~~~

Ok,

or also possible: I think he was in the wrong. or, I think he was wrong. I think he made a mistake. I think he was at fault.

b: Um,,, It isn't that you have no fault. but I think he had a fault about that.(not sure what you are trying to say)

Um, you aren't exactly perfect either. But I think he was partly to blame in this matter.

Um, you are not entirely without blame in this matter. But I think he was also partly to blame.

2)
Hey, Don't you ever knock? I can't concentrate!!

good

3)
a: Don't you have feelings for her? Then ask her out now!
b: Now?
a: Yes, this is your chance!!

4)
a: Can't you hear me?
b: Oh .sorry. what did you say? I was thinking about something.
a: I asked, Which food will you order from this menu? (or: What do you want to order?)

5)
a: Can't you just forget it? It is already gone!!! (It is gone already!)
b: you know, They're important things to me.
a: I know. but you've already spent over  4 hours trying to find that ring!!

(Or, but you've already spent over 4 hours looking for that ring! or, but you've been looking for that ring for over 4 hours already!)