Harvest mature peppers that are green or orange once they reach the size, texture or color you desire, typically in the summer. Snip through the thin stem that holds the pepper to the plant with a sharp pair of scissors or secateurs. Do not tug the peppers off of the plant as this can damage it.
Groom the plant periodically throughout the growing season to prune away any floppy growth as well as any dead, diseased, damaged or otherwise compromised plant tissues. Also trim back any parts of the plant that drag along the soil surface as this can be a precondition for pests and disease.
Prune the plants down to the crown, at the soil line, after the first frost in fall or early winter. Remove the cuttings from the area or till them into the soil as a live compost.