A product life cycle charts the phases a product goes through from its introduction to its eventual decline in the market. To create one, begin by identifying the introductory phase, where the product is launched and gradually gains consumer attention. Next, the growth phase sees increasing sales and market share. The maturity phase follows, marked by stable sales but increased competition. Lastly, the decline phase occurs when sales drop, usually due to market saturation or newer alternatives. This life cycle can guide strategic decisions throughout a product's market presence.