“Señores” literally means “Gentlemen”. This is a polite way of addressing a group even if there are women in the group.
“Tráigame” means “bring me”. Make sure you say “please”/”por favor” at the end of the sentence you use that, otherwise, it can sound like an order and be considered rude.
The word for restroom is “baño”. “Where is the restroom?” is “ ¿dónde está el baño?”
In restaurants in Latin America you can call the waiter “joven” if it is a male. This literally translates into “young man” and is the equivalent of the French word “garçon”. For female waiters, you would call them ”señorita”, or “young women”. It does not matter how old the female waiter is.
The word for fruit juice is “jugo”. Normally you will want to specify the kind of fruit in the juice. To say a specific fruit you would add the word “de”. So an orange juice would be “Jugo de naranja”. You can review the kinds of fruit in Spanish in episode ??? of this Live Lingua Spanish podcast.