In terms of labor exploitation: you can't easily, not individually. Systemically, you will be paid less than the value you provide to the company. Trying to combat this individually would mean you either provide less value to the company, you get more pay, or both. But you'll never consistently reverse that relationship until the overthrow of capitalism.

Providing less value to the company: this is contextual. Basically, you do your job badly or half-assedly. So long as you don't get fired, this is good for you in the exploitation equation in the short term. Longer-term, if it is noticeable it will impact your ability to get more jobs going forward and improve your personal material well-being, which is not necessarily improving the balance for our fight. Socialists who are on the brink of financial collapse don't have as much time to organize, e.g. Also, if you're doing shared work, half-assing it by yourself will make others pissed at you and contradict the very good point made by Mao: it's our job to radicalize the radicalizable by being good examples. People want to emulate those who do good work and help others, etc. People will resent the "lazy socialist" who half-asses it alone and makes everyone else do their work. But if everyone is on board, or there's just one tryhard nerd, or it's not group work, absolutely have at it.

Getting more pay: outside of asking for a raise and crossing your fingers, you can't do this alone. You'd need a union and/or the abolition of capitalism.

In terms of just generally surviving the retail environment: makes buddies at work and commiserate. Retail sucks but it's better if you can bitch about the same things. With luck there might be a comrade or near-comrade there already, too. Also, your quality of work environment will depend very heavily on management, which means it's outside of your control. If conditions become intolerable, your only option will be to leave your job for a different one, so... just keep that in mind. Job-hunting sucks but if you put out feelers on a regular basis you will have more options, won't feel stuck, and will have more luck getting better working conditions in general.

Stealing is praxis but not only if you don't get caught. Only do that if you are 100% confident you will get away with it. No cameras, it's dark, nobody is around, no security, etc. I would tell most people to not steal in general because the downsides of getting caught outweigh the potential praxis. Though I've definitely gotten away with plenty of it :D.