As you might know right now, a cache is a treasure, hidden somewhere. You need information to find it. A description about the area, about the cache, about the exact location. In most cases a GPS coordinate is given and this will ease the hunt for the cache.
A GPS coordinate is quite accurate, but there is always an error of 3 meters (9 feet) or more. For this reason a hint is provided at many cache pages. When a cache has been visited many times, the caches will make a path to it and the soil around it will be disturbed.
There a many different ways to hide a cache:

• A traditional cache with a single description and/or GPS coordinaten of the hiding place.
• A multicache where the cacher has to visit multiple locations / caches to solve a puzzle and/or to retrieve essential information to find the cach.
• A mystery / puzzle cache where the cacher has to solve a puzzle to get the essential information.
• A webcam cache, where te log on the website is valid if you upload a photo of this cam as prove you have been there. You have to be in the picture of course.
• A letterbox / hybrid cache, where there are no GPS coordinates of the cache are available and you have to find the cache with only a route description.
• A virtual cache, where there is no cachebox or webcam, it's just a location. You have to send required information or a foto of the location to the cache-owner to make your log valid.