Adding wood wainscoting or paneling? Remember that electrical boxes need to be flush with the wall. You can move the boxes out, but you'd have to cut the wall open. It's easier to use a plastic or steel extension ring. They're available up to 1-1/4 in. deep.
To install an extension ring, first turn off the power to the receptacle at the main panel, then remove the cover plate and unscrew the receptacle from the box. Pull the receptacle away from the box (don't disconnect the wires). If you're using a steel ring, press a grounding clip onto it and connect a 6-in. grounding wire. Connect the other end to the ground pigtail. Fasten the receptacle back to the box using the longer screws that come with the extension ring.
Turn off power to the outlet at the breaker box before opening the outlet, then test the wires with a voltage tester.