Phil Provost outlines 5 common mistakes made when planning experiential marketing events. The first is having too many companies involved, which increases the chance for mistakes. The second is being unable to properly evaluate and measure the performance of the event. The third is making the brand's message too complex for audiences to understand. The fourth is failing to collect data and follow up after the event. The fifth is prioritizing business goals over crafting a memorable brand experience. Provost advises hiring a solid team to streamline the process and ensure effective coordination of all event aspects.