The first point of the «how to care for anyone» list would be love. And very preferably would be not to forget to clean the cage at least one time per week. Do not forget to add freshwater, food, and bedding as and when necessary. Also, do not forget to pet your guinea pig from time to time. You obviously could not make this animal execute commands, but you must make it not to be afraid of people, especially if you’ve chosen the aquarium cage.