2007 A3 jacking points/locations.

[Chorizo Jackson]

Yes I really am unsure on where to place a jack safely. I get very paranoid with these things.

[OCD-A3]

If you are using the jack that came with the car for roadside tire changes (only use this jack in an emergency, it's pretty flimsy) there are indentations on the rocker panels that indicate where to place the jack.

If you are using a standard floor jack with a circular pad, you can lift the front by placing the jack just behind the wheel and lifting at the control arm mount that's attached to the subframe. To lift the rear, place the jack ahead of the wheel and lift where the trailing arm meets the body. It mounts into a reinforced metal recess, place the jack on the mounting area, not the arm itself.