there are usually spots that the cameras don't reach. just small little blind spots, where at least they can perhaps only see you from one angle. you can wander calmly around the shop, take those things to the area you have scoped out and stash them.
and yes, buy things for real as well, as others have suggested
and don't steal from ur local shop. if ur caught u are more likely to get banned than have them call the cops on u. then u can't go into ur local shop and buy things when u have to.
not all shops have people actively monitoring the cameras. they are mostly for deterrence. try not to get caught on camera but it's not the end of the world if you do.
avoid shops with security guards if possible. at least in my neck of poor europe, most shops don't have them. mostly shop workers won't stop you, and if they try to they mostly won't do anything other than ask you to turn back. when i worked in a shop we were actually told not to engage anyone physically. be very nice to everyone who works in the shops u pick, since workers who like you are less likely to do anything to stop you. and yk be nice to workers generally.
avoid shops in commercial districts where there are likely to be cops patrolling outside. the one time i got caught it was cuz there were cops on the street outside.