Well we bought nearly 2 years ago but I'm sure things are much the same.
Auction prices be prepared for it to go well over, we found add 10% minimum just to have a chance, sometimes would be up to 20% more.
Private sales different, I think you could put in an offer up towards the higher end of what they are asking you could get it, guess would depend on the interest.
We were dissapointed at so many auctions and found where we are now at private sale, it had been on the market for awhile and they kept having to drop the price down, we found it when it was in our price range and offered exactly what they wanted and got it, the next day there was all this other interest so we were lucky we got in first.
I think it would depend on area too, how much of a supply/ demand there is in that area, if they are having plenty of houses up and not as many buyers you may be able to negotiate a better price where if there is a high demand you may end up having to pay alot more than intitially thought.