In the wild, many animals spend a lot of time hunting, foraging or grazing. In captivity, however, if their food is just dropped into their laps and requires very little work to obtain, the time spent on these behaviours is significantly reduced. Many natural behaviours displayed by a species will be based on how they would find food in the wild, and without the need for these behaviours animals may spend a large proportion of their time inactive, which can lead to stereotypies and other negative behaviours caused by the anticipation of food when feeding times are overly routine. There are tonnes of ways to use food in enrichment sessions, but bare in mind that any food used should be part of their daily diet to avoid obesity.
Focus on encouraging hunting and feeding behaviours. Think about where they would find their prey, how they would stalk, chase and catch their prey and any species-specific hunting behaviours or adaptations. Food items including fur and feathers will encourage natural feeding (and sometimes play) behaviours and increases the time taken to consume food.
Think about how and where they would find food in the wild and encourage natural behaviours such as digging or climbing to obtain food, provide opportunities for foraging with live insects for insectivorous species.