The best way to get hired at Costco is apply around August as the application stays on file for three months. They usually start hiring seasonals in September so after you apply walk into the store and ask to speak with a manager and let them know you applied and give them your name so they can manually pull your application. From there, they usually will call you for an interview filled with basic questions like previous job experiences, etc. If all goes well, they'll usually let you know that day or soon after and have you take a swab drug test on site and give you your orientation.

Behavioural questions. Answer with STAR technique and you will be fine. Simply do some research on Costco before coming in, and mention that you have done some activity like fishing or hunting before.