Hey You!

If you want to get someone’s attention – “Hey You!” Is probably not the most polite way to go about it, but it would work.

An extremely polite way to get someone’s attention is to say:
I beg your pardon, sir.
I beg your pardon, ma’am.
I beg your pardon, miss.
(However, I rarely (if ever) hear people say these where I live.)

A typical and still polite way to get someone’s attention is to say:
Excuse me, sir.
Excuse me, ma’am.
Excuse me, miss.
(Adding sir, ma’am or miss at the end make it more polite. You don’t have to use them though.)

If you’d like to get the attention of a friend, you can simply say their name.
“Sally…”

You can also use “hello” or “hi” as a way to get someone’s attention.

Another way is to get someone’s attention is to clear your throat. (But, you have to be close enough to the person for them to hear it).

If you are trying to get the attention of a whole group of people, you could whistle, if you can. Or, you can say, “Listen up!”