It is most fun to have some type of theme for a treasure hunt. It can be pirates or safari or anything else that your child is interested in. You first need to decide what type of hunt you want to plan. Simple treasure hunts can be planned by deciding where to hide a treasure and then working back from there in planning your clues. Make simple rhymes that tie into your theme and incorporate the location of the next clue.
You can also purchase hunts that are already professionally created for you. The ones on the following site all come with complete directions and tips for running the hunt. They can all be customized for your location, time frame, etc. http:/www.mastersofthehunt.com/buy-a-scavenger-hunt.php