What is a polite or neutral way to ask for someone to step out of your way? 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?
The most polite way is to use:

借过


  excuse me
  -ABC


If you want to sound politer you can add a 一下 on the end: 借过一下.

让 is not super polite, with or without a 一下 but you could still get away using it.

A simple 不好意思 would also suffice but is not as polite as 借过.