The best way is to just take the whole situation as a joke. If she starts bull**** over something small then make sure you are not letting it emotionally effect you in a negative way, have an upbeat mood and turn the situation into a joke. Over blow it even more.
For example:
she says:
I hate you when you leave the toilet lid up.
you say (in a upbeat, positive mood): OMG, you are right. I am a horrible person, it's such an incredible mistake by me. Baby, PLEASE, can you EVER forgive me?
If you blow it way over and don't get butthurt about it then it will show two things: that she was silly that she started a fight over such a small thing and it will increase the attraction she has towards you because she can see that she just can't get to you.
The small fight is basically a **** test to see if you really are the attractive man you seem to be. Take these situations as an opportunity to increase her attraction towards you.