This is a simple circuit to control the direction of a DC motor, with the capability to turn it off.
Step 1: Nothing to It...
There is really nothing much to explain. A simple switch will give you the capability to reverse and switch on/off your motor. A switch, like anything else can wear out, but with only one part to deal with, you have less of a chance of paying for a bunch of more expensive components when it comes time to replace them.
Step 2: Wiring the Switch
This diagram shows the DPDT switch, with a center OFF position (NEEDED if you want to be able to turn your motor OFF) The + and - are the battery terminal hookups to the center (COMMON) terminals of the switch. The numbers (1 and 2) indicate the connections made inside the switch when the switch is in the ON (1) position or the ON (2) position. NOTE the blobs. It shows that the wires are connected. All other wires are just passing over each other. One other thing... You can use TWO SPDT switches side by side so long as you physically clamp the toggles together to achieve the same effect. Having the switches in the opposite directions will connect both switches to either positive or negative on the battery, and your motor won't be running.