Definitely as pp have said ask about what makes a good candidate and/or if there are any outstanding questions they have about you.
Other tips I had which served me well :
look up the company on Wikipedia. Memorize the basics about them - number of employees, where they have major offices, name of CEO, key competitors etc. Most people don't do this and being able to throw in a few facts about the business if they ask what you know about the role/company always looks good.
Also have a short patter down summarising your career, skills etc. If you know you get nervous, repeat it til you've got it absolutely by heart and can reel it off. Quite often the first question is 'tell me a bit about yourself' or something similar and having a prepared spiel gets you over the worst of it.
A similar spiel about why you particularly want this role (and why you'd be good at it) will probably serve you well too..
If they offer you a glass of water, take it. Then take a sip before you speak if they ask you a tough question. it gives you a moment to think, and compose yourself before answering (and helps with the dry mouth you get with nerves).
Lastly don't forget the interview goes both ways - it's a chance to see if you like them too. Asking things like why the vacancy is open, and why they're looking to fill it externally rather than with an internal promotion can clue you in a bit - it may well reveal things like high staff turnover, limited opportunities for promotion or that the company is growing rapidly.