How to order things in Russian and/or ask if it is ok

So I've learned to say можно.

For example можно ... coffee, можно take photographs, можно a postcard, and so on.

I have a feeling that there are better ways to order things. For example; what is the best way to order a coffee in a restaurant?

And how should I ask in a museum if it is ok to take photographs?

Thanks.

Принесите мне кофе, пожалуйста.
(better to ask to bring the menu first: "Принесите мне меню, пожалуйста." At least you will see prices, and whether they offer different sorts of coffee.)

ok to take photographs?
- У вас можно фотографировать?
yes, but only without a flash
- Да, но только без вспышки.

Можно is pretty much the same thing as the English verb 'can'.
Можно мне кофе? Can I have a coffee?
...
Of course there are many ways to order things in Russian; it's just about the same as in English.
You can just bark "чёрный кофе, и побыстрее, я тороплюсь" (which is 'coffee, and quickly, I'm in a hurry') to a waiter and the only his responce expected is saying "Ok" and running for your coffee. Though things like that are rather rude.

You can even say just "кофе" and that's just fine, but oops, that's where you're at a risk of the waiter falling into a wordy explanation of what sorts of coffee they can offer to you.

Thanks Medved.

Yes; I've experienced the second case - of being offered a bewildering range of choices of whatever it was I was trying to order.

I think I've got the basic idea that incorporating a dative мне somewhere into the request helps and is considered polite.

Thanks both.

мне appears just at 0min35s
https://www.youtube.com/watch?v=OJ-BUbrlNhU
Doesn't work every time I guess :)