Three main types..
1. Why questions. Why did you choose this subject for highschool. Why are you applying for this company. etc.
Be honest, be genuine - easy to come across when you are genuine and focused by nature. Lots of these questions are basically warm-ups but you can really make a good impression.
2. Behavioral queswtions. Tell me about a time when you had a conflict in a team environment. Tell me about a time when you had to utilise your leadsership skills.
These are usually the gut of any interview. These questions get recycled to no end so if you have multiple interviews the practice you'll get from answering them piles up fast. Answer them in the form of quick background info -> problem -> resolution and most importantly -> WHAT YOU LEARNT FROM IT
and, less frequently,
3. Psyche/throw you off questions. Whats 27x33? How many cafe's are there in Sydney? Why are manholes round?
If they throw in one of these then here is where you can make one of your biggest impressions (especially if your CV isn't very pretty). For ones that are answerable (like the maths question) just stay calm, ask if you can do it on paper (they'll most likely say yes)... For ones that are completely lateral like the cafe question just come up with a reasonable way of estimating an answer and go over the steps you used. For ones like the manhole question... There's a real answer, but there's a good chance you won't get it. Whats most important is that you remain calm and friendly about it, don't get stressed/frustrated (they're putting you in the hot seat for a reason)
Most important interview tip I can give: break the 'formal' barrier asap. Harder to do in a panel-style interview, but the quicker you're talking to them as if they're your friends and not people that are giving you a job the better your chances. That's called building rapport - it's something they look for. You can have the prettiest resume, best answers to interview questions, but if you feel clinically detached to the world then you won't have a very good chance.
And by talking to them as friends I don't mean slang, "umms, errs", etc. You know what I mean!
Edit: For the noobs.
"Rapport is one of the most important features or characteristics of unconscious human interaction. It is commonality of perspective, being in "sync", being on the same "wavelength" as the person you are talking to."