Re: How did you approach your DAD about marriage??
Eh?? ^
I think you should sit down with your parents (depending on how open your parents are with discussing such issues) and discuss it with your father.
Daughters are always ladli for their father 
If you’re close with him and can’t open the discussion, then try hinting in a general conversation with your mother and father, that you are ready to settle down.
Sorry, I’m not of much help! I haven’t got to that stage yet ! hehe