Agree with summer here. You use 不好意思 to catch the attention of a person, before asking a question or a favour. Or, you are asking for an excuse after doing something bad. Exactly how you would use "Excuse me" in English.

不好意思=bù hǎo yì sī usually using for asking somebody to do something for you.

Depends on the context. When getting off a crowded bus, I usually say 麻烦您， 让一下

"打扰一下 " this is best way

不好意思 麻烦一下