Good thread this one
I'm not sure about the cardboard car idea
The best races (most enjoyable) for me are when you feel a mutual respect for and from the other drivers around you, as others have said it nice to leave room and be left room when cornering.
Practise braking and cornering off the "racing line" because this is where you have to drive to overtake safely/cleanly, and as others have said you need to drive slower on these lines.
Someone said to me a long time ago you never want to just follow the car infront, try to anticipate where you could line up a pass even if if takes several corners or laps a clean pass against a worthy opponant is a great feeling when you get it right.
If you do accidentially contact the car infront, be it a tap to the rear under braking or knocking into the side of them close to the apex, always lift to allow them to stay ahead, "dirty passers will dive into the apex and use any car thats on their outside to deflect them around the turn, If you need to contact the other car when passing just to stop from flying off the outside at exit, your not doing it properly
Know your cars capabilitys on a given track, if your not in total control of the car don't try a risky pass, however we've all tried that last lap last corner suicide dive up the inside and got it wrong
League racing always looks more aggressive than some pickup racing IMO because league racers practise together and form a "trust" with each other, making for better races and drivers with similar mindsets to one another all knowing where each others car is at any time during the close battles, giving room when needed and fighting hard.
Never ever allow your frustrations to show in your driving, even if your wrecked for races in a row never do it back, its a sign of weakness and imaturity, far better to grin and bare it and theres always the next race.
be very aware when in close traffic of other drivers/cars both infornt and behind, and all around you, sometimes when braking, you can spot someone in your mirror who has completely missed there brake point and "side-step" the rear impact, a proactive approach to racing is nessecery to driver self development, and keeps you in the race.
SD.