I spend my days teaching racing drivers in real cars how to go faster - see
www.race-instructor.co.uk
I was fairly handy with a touring car in the late 90's and having gently started off roading again am getting some good club results with a mad monkey.
I can't help but observe other drivers and try to relate to my day job.
These have been indoors on carpet and outdoors on astro with off road cars.
In real cars most drivers are able to pick up getting the car from the apex to the exit very well. The hard bit to drive and the area where time is made is the point from braking to apex. Model cars are largely the same.
Areas where I see a lot of mistakes:
Braking - it's not an on/off switch. In areas that require brakes for 4wd should be firm initially and then eased off as the corner approaches. 2wd requires a slightly softer initial brake pressure to cope with the rear wheels unloading.
Steering - again steering input must vary with speed. As a basis the faster the speed the slower the steering movement. Remember that as the car slows down entering the corner the lock can increase.
Steering lock - I see a lot of cars where the turning circle is set for the larger corners to make the car easy to drive. When the car arrives at a hairpin it can't turn tight enough to get the best line. Set your steering to get the best in the tight bends and then don't use full lock in the faster corners.
Power - don't get on it too soon - again more of an issue in slow corners. If you apply 25% power at the apex but then are only at 50% at corner exit, that wont be as fast as the car with 0 throttle at the apex but 100% just after.
Vision - again a major strength in racers of big cars and little ones. When practicing make sure you look at the car with your eyes focussed ahead and turn your head to look at the car. If you start moving your eyes about you lose your best focus and peripheral vision.
In recent races I've been trying to analyse my own driving to figure out where I'm looking relative to the car and the track. I believe that I'm focussed on the car at all times but am looking for my next reference point in my central peripheral vision. This way I can judge the cars speed and heading relative to the apex of the corner.
Watch a novice / new racer and generally they react to the corner as the car arrives at it. Try to look at the car and spot the next corner in your peripheral vision. As mentioned in an earlier post a slower moving car generally crashes less. Just as in big cars when the car is faster your vision needs to move faster with it.
Hope that makes sense and is of some use!