You need to start by doing little harmless things first like letting some air out of the front right tire and the left rear tire so the sensor light goes off.
Then fill the bed to the top with cow shit.
Smear some dog shit behind her driver side door handle.
Tweek all her mirrors.
Chew up about 100 packs of bubble gum and on a hot day put it under the right front tire.
Hang a sign from the back saying" I'm a lesbian".
Fill the center caps on the wheels (if she has center caps) with small rocks.
Take an old car key and break it off in the drivers side door lock.
String a bunch of beer cans together, tie it off underneath the rear somewhere and lay em up on the spare tire. Then when she hits a bump they fall down and drag behind her.
That oughta get ya started bro!