Look for the Visual and Audio Cues
When you are hunting your prey, keep an eye out for red vibration marks. If a survivor is nearby and they are running around, they will leave behind these red marks, giving away their location. Head over to them and take them out!
When you are looking around, if a survivor enters your line of sight, there will be a red exclamation mark over your head. If they leave your line of sight but they are still in the immediate area, a yellow question mark will appear.
Keep this in mind, as some survivors may get a little cocky and try to slip past you behind your circle. It helps to keep your head on a swivel to expose any would-be daring survivors.
If you are having trouble finding anyone, just be patient. When a survivor hits a switch, you will see an indicator that points towards the switch. Just wander in the general direction of the switch and you are bound to find someone!