“Excuse me. Would you mind watching over my stuff for me for just a minute?”

You're studying in a coffee shop by yourself. You want to get up to use the bathroom, but you're worried that someone will take your books or move them. You ask a woman who's sitting next to you:

Excuse me. Would you mind watching over my stuff for me for just a minute?

Excuse me.

Say "Excuse me" to get the attention of strangers in a polite way.

In some English-speaking areas, it's also polite to add "Sir" (for men) or "Ma'am" or "Miss" (for women):

Excuse me, Ma'am. You dropped this on the sidewalk back there.

But since these titles are actually thought to be impolite in some areas, it's best to listen first to see if other people around you are using them.

When you pronounce "excuse me", it can sound like "'Scuze me"

watch over (something)

To "watch over" something means to guard and protect it. But "watching over" something is not as serious as "guarding" it. A professional "guards" things like expensive artwork, an empty office building, and so on. But regular people can "watch over" things like someone's computer or someone's teenage child.

People often say that God "watches over" people as well:

God, we pray that you watch over Richard and his family in this difficult time.

Would you mind (doing something)?

"Would you mind ___ing?" is a good way to politely ask for something that isn't too much trouble for the other person. Some more examples:

Would you mind giving me a hand with this?

Would you mind covering for me while I'm out?

Would you mind forwarding me his reply?

(do something) for me

Use "___ for me" when asking someone to do something that you want. It's a casual expression.

Close the blinds for me, would you?

for just a minute

"For just a minute" means for a short length of time. It doesn't mean exactly one minute.