You can carry four companions. The more you have, the better. There are three types of crystals to feed them, depending on their color. Have a mixed set of companions to use all the crystals that are obtained. Each time you power them up, their experience points increases. They will eventually level up, and have their power-ups last longer. After you get four companions, purchase a mount for the extra bonuses. Focus on getting rare companions. Different creatures will give additional abilities to your character. Try not to have more than one creature with the same ability (for instance two of them that have the ability to have the coin chomper activated). An exception is having two creatures with the same ability but with different colors, because they can be activated with different gems. Some useful rare companions are the Lightfoot Cassowary that can do triple jumps and the Slowfoot Tortoise that will let you run at slower speed.