<human>:  What preparation should I do when painting a wall?
<bot>: Before painting a wall, you should do some preparation to ensure the best results. This includes cleaning the wall surface, filling in any cracks or holes with spackle, applying painter's tape to the sides of trim, doors, and windows, and covering furniture and floors with a drop cloth. Depending on the wall's current condition and the type of paint you are using, you may want to use a primer or sealer before starting the project.