I am wondering how to order tapas when I get to spain. I have books for translating ingredients, but for example, when you order 1 item, is it a plate of that item, or literally 1 piece of that item? Can I expect patience from restaurant staff?

I don't think one usually orders tapas in restaurants.

You can order media racion (half portion) or una racion (full portion) of something you plan to share (patatas bravas, for example) or, if you just want to sample something, ask for una tapa (de anchoas o de sardinas). Tabernas in Madrid usually give something with a drink like olives or small fish filets (boquerones en vinagre). There will be a glass 'box' on the bar covering many things that you can order as tapas: Tortilla, ensalada rusa, chorizos en salsa de tomate, etc., etc. Point at what you want and tell the counter person how much.

They'll usually be quite patient with tourists, especially if you're young and pretty.

it is usually a small serving of what you ordered. some places even give you the option of ordering a larger portion of the item.
as for patience in my experience it is the customers who need patience as they do not run on the american idea of hurry customer to free up the table. after you order and get your food they leave you alone. you need to ask for the bill.
have a great time!

Usualy tapas are shown on the bar under a glass cover, they idea is that you order what you see, so just point them out and they will serve them to you.
Many bars like to name tapas on their own way. So they don't expect every customer to know the local name , so you have a look around and point what you want. That is the way locals do.
If you get serve too much just say " demasiado" and they will cut it by half.
Another good system is looking around what other customers are eating, and if looks appealing to you just point it and say " Como eso" .
And " Que aproveche"

Your best bet is to order something you might like that people are eating in another table, or go to the counter and see with your own eyes something you might like.
Do not ever dream in trying to understand the waiters, I speak Spanish ( mother tounge) and I never understood the list of tapas as told to me by waiters .
Also be aware that in most places there is a section of the restaurant set aside to eat tapas and another for more formal dining. Hope you enjoy them because most of them are delicious.