Depending on the job, and I'm presuming it's one that doesn't require a lot of specifc technical knowledge, you will be asked lots of very general questions, about why you think you are right for the job, what skills you can demonstrate from previous jobs that would be good for this one.
So use everything you did from previous jobs, even if it seems small and you only did it once, to embelish - not lie.
Also, and this is key in interviews imo: know the company so do a little reasearch on the web so you know about them, their history, culture or w/e and drop it in to conversation or ask about something you saw on their website.
And always, always, have a good question to ask them. Particularly one that makes them think so they remember you.
And wear a suit