Determine what materials comprise the entertainment unit. Typically, entertainment centers are made of melamine-coated plywood. In other words, the surfaces are made of pressed wooden particles with a glossy, faux-wood melamine finish applied to the exterior. If you're not sure whether your unit is truly made of real wood or simply pressed wood and melamine, try chipping off a small piece from the back or a corner where nobody will notice. If the wood grain continues deep into the entertainment unit, then it is real wood. However, if you notice pressed particles, then you're dealing with a melamine unit.
Unscrew any handles or other protruding hardware from the entertainment unit.
Use painter's tape to protect any areas of the unit that you don't want to paint.
Place the entertainment unit on a large tarp in a well-ventilated area.
Wash the unit with soap and water as recommended by LoveHome.co.uk. A clean surface will ensure better paint adhesion. In the case of a melamine unit, you can fully saturate a rag for cleaning purposes. The melamine acts as a protective buffer between the pressed wood particles and the water. For a wooden unit you'll want to use a rag that has been rung out and is barely damp; if you use too much water, the wood will become saturated and potentially water damaged.
Wait for the unit to dry completely after you're done cleaning off excess dirt and dust.
Apply primer to the surface using a foam paintbrush for melamine or a regular bristled brush for wood. You can sometimes skip priming when working with wood, but melamine always requires primer since the initial surface is so slick and does not accept paint easily.
Paint your wood or melamine entertainment unit using a foam roller and acrylic paint. The roller alone will not reach tight corners, so you must touch-up the edges using a foam brush for melamine entertainment units. In the case of wood, a regular bristled brush is also acceptable for touch-ups.
Wait at least one hour before applying a second coat using a foam roller and brush.
Wait at least 24 hours before removing any painter's tape from the unit, and wait a full 48 hours before returning objects to the entertainment unit and reattaching the hardware.