In English I would say "excuse me". Some possibilities that come to mind are 请让，对不起，不好意思. I believe I have heard someone say "让!" before. Is that considered impolite?
In most cases "劳驾" is the proper way: polite, effective and simple. If it doesn't attract the target's attention, you just need to repeat it louder.
"让" certainly is impolite. "请让" could be much politer, but still not as polite as "借过". The reason is that "过" indicates the intent of yourself (I want to pass), while "让" means request to others (You, make way).
"请让我过一下" is better than "请您让一下" for the same reason.