Best advice: Get to know everyone. There's no such thing as a bad connection. Being on good terms with the other hardlines team members means they won't just see you as seasonal help who'll be leaving soon, but rather, a person who's worth helping now because you plan on being around for a while. Get to know your fellow cashiers because some of them know more about working the lanes than most GSTL's, and they'll be the one's bailing you out when a guest tries to quick change you or take advantage of the coupon policy. Get to know all of the team leads, especially your sales floor team leads (hardlines, softlines, consumables) and GSTL's because they'll be the one's who will push to keep you beyond January (if you're going for a permanent position). And get your name out there to the ETL's by offering to pick up shifts when possible, responding for backup when the front lanes gets busy, and doing your best to provide good guest service while seeking out ways to improve your performance.
Just like any business, connections will help you survive the chaos that is seasonal work.
And most of all, Welcome, and enjoy your time here!! =)