Read books about car behaviour (Carroll Smith's books are really
good), watch racing videos, watch replays of other drivers, compare
your laps with record laps using GPLDump and Spygirl, download
different setups and try which one suits you the best, read the superb
trackguides at http://lightsoutracing.simplenet.com, read everything
at riccardo nunnini's site, and ehhh.... practice.
Your laptimes are really below average (no offence, I'm not that good
either) but since you post here so much I guess you drive a lot in
GPL, you really should start to improve over time.
The Ring for example, I just read you are still in the 11 minutes. How
much do you drive there? Do you know the track by memory? The most
important thing is that you race without driving the car off the road.
Try to drive a little bit slower in the corners which you have
difficulties with, focus more on staying on the track. If you can
drive on the ring without having to use shift-r, driving below 10
minutes should be no problem anymore.
Of all the above tips, I think reading the circuit guides at
http://lightsoutracing.simplenet.com is the best tip, it really helped
me a lot. All the track guides are there, and the writer just started
writing the guide for the Ring, that should be completed in a couple
of weeks.
Good luck, don't give up.
Andre