Downforce = aerodynamical grip - car forced into the ground to corner at higher speeds

Front/rear wing angle - This is all about the trade-off between drag and downforce. The sharper the angle, the more downforce the car has, so you'll be able to corner at higher speeds. However, the straight-line speed will be lower, as there is more drag.

One of the easiest ways to set a car up to oversteer is to put a lot of front downforce on the car, but much less rear downforce. The car will have more front end grip than rear, and so the back end will slide out, and oversteer is achieved. To achieve understeer (I'm not sure why anyone would try to...) you just need to put more rear downforce on, so that the front doesn't have enough grip to turn in at high speeds, and the rear won't 'rotate' easily.

Gear Ratios - just like all aspects of car setup, these will differ from track to track, and often, a driver might choose to go against the 'expected' gear ratios. For example, at Monza, the long straights mean the cars are normally long ratio geared, to reach higher top speeds. However, Sebastian Vettel went for a short ratio, sacrificing over 10mph in top speed, but his acceleration meant he reached 200mph earlier up the straight than anyone else.

Short = Acceleration

Long = Top Speed

 Soft = fast

Hard = long lasting

Tyre choice - in my view, this does count as part of the car setup - and it can be changed during the race. Soft tyres are faster, and so they're the tyre of choice during qualifying. However, they wear out faster. The slower hard tyres would then be expected to be a tyre to run in the race, but because of the speed differential (approx. 1 second slower per lap), the teams only run the hard tyre for run stint during the race, and use the soft tyre over multiple pit stops.