Try to keep your end goal in mind and take solace in the fact it's all just a means to an end. It won't be forever.
Try to find some allies/friends there as quickly as possible. Maybe do something simple but nice for the people you value there. Stuff like buying then a coffee. Leaving nice things to share in the communal areas. Don't go so far as to allow people to take advantage though. Just the odd nice gesture. If it's taken for granted you'll just be armed with a bit more info about the character of the people around you and be able to use that info in chosing who you do or don't get friendly with.
Keep any negative opinions of your coworkers to yourself no matter how justified. Don't let yourself get involved in any back biting even if it's warranted as people can use your words against you at a later date. Best not to provide any ammunition for them even if you currently trust them.
Keep your focus on the job at hand and reward yourself for milestones you achieve on your route to your goal.
Remember that bullies and assholes are that way because of a problem they have and its not a negative reflection of you, your worth and/or character. People just suck.
After a bad day try to find some media that you can relate to as you wind down. That can be particularly helpful if you don't have people you can lean on in your home environment. There are a few good films and comedy series about people working in the retail environment. One that comes to mind is
The Promotion. It's a bit of a hidden gem of a film. Great acting from John C Reilly and Sean William Scott.
All kind of obvious stuff but it's easy to overlook when you're in the middle of a situation. Good luck with your job. Try not to let the bastards grind you down. : )
