Systematic describes something that is planned out and careful. In your systematic search for your mother's car keys, you start in one room, looking everywhere from bottom to top before moving to the next room.
Use the adjective systematic to describe things that are orderly and efficient. The Latin root of systematic is systema, an arrangement or system. Think about a multi-step process that you have found the fastest and best way to complete — you do it over and over. You might be systematic about packing for a long trip or the way you travel up and down the aisles at a grocery store, probably with a list in your hand.