1) a plug is used to stop water from escaping. A bath plug is what you might find in your bath tub:
2) A "wake up call" is a call scheduled to wake you up at a specific hour. It is a service most hotels provide for free. So you would say:
"Can I get a wake up call at 7:00 AM."
3) A shower block is a group of showers. Usually in a sports locker room where athletes shower and change into uniforms.
4) When one makes a reservation at a restaurant, they usually "put it under" their name. You put things "under" a label or category. For restaurant reservation, it almost always is a name.
I have a reservation under "Smith".
5) When you order at a restaurant you can eat it at the restaurant (to stay) or you can take it home with you (to go). So, when you say that your order is "to go", it means that you are taking it home.
6) Yes, "I'd like to order" is used mostly at a restaurant. Although, it could also be used at a bar.
7) draft can mean many things depending on the context.
draft: a current of air
draft: a written document. Sometimes, when you modify this written document, each version of it is considered a draft. A rough draft means the very first version of the written document; it is almost always modified. The final draft is the version that is used for the purpose it was written. Like speeches or legal documents. There can be various version of that same written document known as first draft, second draft, third draft, etc.
draft: when talking about beer, it means that the beer is stored and served under a pressurized system of taps and kegs.
draft: a sketch or a hand drawn schematics
8) To get a "cash advance" means that you would like to receive money before it is owed to you. You usually make this request from an employer or from someone that is due to pay you some money in the future. For example, if you make $300 a week and are due to be paid on Friday, you might ask for $100 on Tuesday to pay for an emergency. This is a cash advance.
9) "Can you ship this" is used for anywhere. Not just a market. If someone has a product or an item that you don't want to or are not able to take home your self, you can ask them if they can "ship" or "deliver" this item. The word "deliver" is usually used for foods and "ship" is used for items such as appliances, electronics and furniture. Although more and more people are starting to use the word "deliver" for these too.
10) If you don't want to use units of measurement ("Cut about 10 inches"), you can always use your fingers to demonstrate how much you want cut:
"Cut about THIS much (your fingers will indicate how much THIS is)"
11) The gentle cycle is used on your washing machine to wash delicate clothing.