I am totally a failure....

My sister argued v my dad just nw.I knew it...act the main reason is my dad always dont recognise wat she done and always compare her v me.My result is higher than sister n i seldom do against my dad.So,my dad always compare me and my sister.I tell to my dad not to do so but he still dont listen to me but say sth that my sister did not respect him and oths thing .I really hope i can return to the past n prevent today's situation to happen.I knew it is sth wrong in my family education but wat shld i do to solve it?I really dont know hw to do...I am a very weak person in deep.