assalaamu alaykum sister,
you must first create respect for the Quran and ahaddith before you use them on people.
say things like... if Allah said this to you would you listen to him?
if they say yes, then point out to them that the Quran is the word of Allah and should be read, recited and respected as such.
obviously if they say no they have fundemental issues it might be best addressing through methods more familiar when giving da'wah to the kuffar as opposed to naseehah to the muslims.
ask them if they love the prophet Muhammad (saws)?
ask them if Allah (swt) tells us to obey him in the Quran then who are we to disobey?
when they have this love of Allah and his Rasool (saws), the Quran and ahaddith, then everything else becomes easier to deal with.
assalaamu alaykum,
Daw'ud