It'd be much easier to do that if all parents limited screen watching. That way your kid isn't rushing off to watch tv/computer/games at so and so's house.

In home, you just limit them. Start by taking small chunks off the total screen time slowly. They'll notice, but will (just barely) survive. Better yet, limit the whole family. Of course, you'll now have to spend more time with them. Harder if the dad unit isn't on board, but not entirely impossible.

It's like most everything else, moderation is key.