As a current GSA, I'm in the same boat, my advice: be good at what you do. Make sure all your check lane ends are full so they can drive sales, make sure your soda coolers are full, double check signing in-stocks on everything up front. Lead your team in a respectful manor. Have your cashiers/cart attendant fill ends do abandons when they're not busy. Speed weave as much as possible and drive red-cards and yes ask to be a captain, my etl put me in charge of the red-card program as well as loyalties we were 5% conversion black Friday week. I'm still a work in progress and I have several things i need improving on but I'm trying and those things are a great start. Also like a previous poster said,gain the respect of your team they will go the extra mile for you if they respect you. Good luck and have fun, don't get stressed out it's just a job.