Use a 60 watt bulb and wire the light using three or four feet of slack cord. Gasoline lanterns such as the famous Coleman version produce an enormous amount of useful light and cost pennies to operate. These lanterns are especially helpful when a reflector is used to direct the light in one direction. The problem with gasoline lanterns is they require a delicate mantle that's easily damaged if the light is bumped or dropped. In addition to serious light, game trailing after dark requires considerable patience.
Progress is often very slow and the temptation to walk ahead can be overwhelming.
Moving too fast is an open invitation to disturb what little blood or other sign is available. Force yourself to move only from one drop of blood to the next, taking care not to step on or otherwise destroy sign in case it becomes necessary to back track. Snap off twigs along the blood trail or mark the trail with pieces of tissue paper or flagging tape. When the trail gets tough to follow, a glance back over the route covered will help suggest a general direction the animal is moving. Most of the time a wounded animal will not make a lot of twists and turns, but rather choose to move in a general direction making subtle directional changes.