Research the company. Find out exactly what they do and what they're looking for. If it's a big enough company and you're good at disguising your voice, call and ask to speak with someone in HR. Say you heard about the position and are interested in applying, ask what sort of experience/background they are looking for, answer everything with "yes" and "of course" to keep them talking and make sure to ask about benefits/work environment to make it seem benign.
Research the skills they say they want, get familiar with the concepts of things you don't know, and learn how to relate that to your own experience.
Example question - What experience do you have with -xyz-? (assuming -xyz- is something you have no experience with)
Example answer - I'm familiar with -xyz- (true because you researched it) although I've worked mostly with -abc- (your experience that most closely relates) when I've done -zzz- (task that most resembles what you'll be doing in the position you're applying for), but if I were to work with -xyz- I would...(explain basic concepts of -xyz- that would be appropriate to accomplishing the task).
I'm actually disturbingly good at job interviews, so if you want to give me a random question I can give you a random answer and prove that you can say wonderful things while having absolutely no idea what you're talking about (: But mostly you just want to do a lot of research into exactly what they want, then figure out how to say the things that will make it appear that you are the person they want.