basic checks:
1. take the oil cap off, is there any milky residue bit like mayo - if so then possible gasket on the way out.
2. check the dipstick, how much oil is in the engine. - if its near empty could be a sign of poor care or oil burning or both
3. check panel gaps, are they all pretty even. do they line up etc. any abnormalities could mean crash damage
4. similiar to above check paint i.e. is it the same all round or is there any inconsistency's could be a sign of repair.
5. push down on all 4 corners, suspension should bounce slightly, if it keeps bouncing, shocks might be going.
6. check tyre wear, have they worn evenly, if not then there are camber issues.
7. put all the lights on check all bulbs work etc.
Engine checks:
1 does it turn over first time or does it struggle, if struggles could be battery or alternator
2. are there any unusual sounds, clicks whines clonks etc
in cabin:
1. check all buttons work, seats move, aircon comes on, if it has power to it does it do what its meant to.
2. with engine off first. try all the gears, do they slip in easily,
3. conditon of seats etc, does the wear look like it matches the mileage. (if the car says 30k but the seats look like they've been to the moon and back then car might ahve been clocked.
on the drive:
1. hard acceleration, does it pull well or are their hesitations
2. do some gear drops. change down from 5th to 3rd 6th to 4th 3rd to 1st. etc, this checks the gear box and syncro's any issues should show themselves.
3. get car to 30-40 mph in 3rd, then drop in to 6th and flaw the pedal. if clutch is good the engine should struggle but slowly accelerate. if clutch is bad, the revs will suddenly jump up like your reving it.
4. check it goes it to reverse.
drive the car at a range of speeds, see if any strange noises.
5. take the car up to 70 80mph, any vibrations through the steering, will show if wheels need balancing etc.
6. a good drive should show up things like crabbing (been in a crash) is steering tight etc.
Zed specific:
1. with the door open, get the car to pull forward slightly, and stop, if you hear any clicking means the car has the clicky axle problem. not a major issue, just annoying. and relatively easy to fix.
2. does the bose skip under use with a CD
if any of those points come up it should give you bargaining room for discounts etc. hope that helps