I am currently attempting to increase my level of conversational Spanish, and so have been visiting a few Mexican Restaurants to speak to the staff there. I am still in the early stages, so I'm just trying to memorize simple phrases and sentences that I might be asked or I might personally use.
I found plenty of excellent quotes to study, but I would appreciate it if a native Spanish speaker confirmed that these are correct. It would be very frustrating to become fluent in faulty Spanish. 
¿Puedo ver el menú, por favor?- Can I see the menu please?
¿Qué desea comer?- What would you like to eat?
¿Qué desea tomar?- What would you like to drink?
¿Qué desea ordenar?- Would you like to order?
¿Si? ¿Qué quiere?- Yes? What do you want?
Un momento, por favor.- One moment, please.
Como plato principal quiero…- For the main course, I would like...
De primero, quiero… / De botana quiero…- To start, I would like...
Para beber, quiero…- To drink, I would like...
Necesitamos más tiempo para decidir.- We need a little more time to decide.
Estamos listos para pedir.- We are ready to order.
¿Qué más trae el plato?- What else is in the dish?
Quiero…- I'll have...
¡Buen provecho!- Enjoy your meal!
¿Cómo está todo?- How's everything?
¿Todo está bien?- Is everything okay?
¿Quiere algo más de tomar?- Would you like more to drink?
¿Quiere algo de postre?- Would you like some dessert?
Por favor tráigame la cuenta.- Please bring the bill.
Any help that can be given is appreciated. Muchas gracias.