It depends on what maintance has been done on it, I know there are a few people on here who could give you some info on what to check to see.
How long is the warrent for?
How many miles do you average?
(will let you know how many months till your now out of warrenty)
Did it come with a user manual?
(If so look inside to see if the previous owner kept a record of all
checkups and oil changes)
Do you know the password for the radio?
(if you do any work on your car that requires you to remove the
battery you will need this password to listen to your radio/CDs)
I know if you look at the past smog check, the reading will let you know how good she is running.
Open the oil cap and look at the oil on the inside. look under the cap! This will let you know if the previous owner ran her hard or was not good with regular changes.
Remove the 2nd spark plug to see if oil is leaking into that area.
If there is no oil check the tip of the spark plug to see if it is running to rich or not rich enough.
Put a light on the belts, and hoses look for cracks
See if you can get someone to check your OBC to see if the computer is monitoring any past errors/warnings.
Just a few things I check when doing my quarterly maintance on my baby.
Hope the above helps,
Mothman