High value treats
High value treats are very tasty and desirable foods your dog really likes. Generally human food is considered much more desirable than dog treats. Hot dogs, roast chicken, cabanossi, cheese are all very good.
Treats should be soft and bite sized. They have to be big enough to be worth working for yet small enough that they don't take long to chew/eat. It is also good to alternate what you use for treats or use a variety, to keep it interesting for the dog.
Make sure you factor in treats as part of your dog's daily food intake.
If your dog isn't motivated by food, you will need to find something else that he or she gets excited about. It could be a ball or a toy, or simply a cuddle and praise from you.
Balls and tugs
Breeds with high prey drive often get quite excited by chasing a ball or tugging on a rope or toy. All these can be used as a high value reward.