The major difference between painting indoor paneling and painting a regular wall is that indoor paneling needs to be sanded before the primer or paint can be applied. Paneling is harder for paint to adhere to than a typical painted wall.
To begin, first clear everything away from the walls of the room that is being painted. Clean off the walls using a dish liquid and water solution. When the walls are clean, use fine-grit sandpaper to softly sand the walls. This helps the primer and paint stick to the walls. After everything has been sanded, wipe down the walls with a damp cloth to clean off the dust. The room is now ready for paint. Use painter's tape along the edge of the ceiling and around any trim or windows that are not going to be painted. Make sure to put down a tarp of cloth to keep the paint off the floor. After the wall has been prepared, begin by cutting the edges with primer and then using a roller to apply an even coat of primer over the entire wall. To ensure that the shape of the paneling is smooth, run a brush down the grooves to remove excess paint. Let the primer dry for 24 hours, and then apply the paint. Cut the edges first, and then use a roller to cover the walls. It is likely to require multiple layers of paint.