This is what i would advise to someone intending to come to the CTRA servers for the first time.
Check what combo the server is running.
Join it and watch a race to see what sort of times the field is running.
Join a the end of the race and ask (politely
) one of the front runners for a setup
Go back offline and run some practice laps on that combo to make sure you are familiar with the track and car, and to see what sort of times you are running compared to the opposition.
Join the server and in your first race let the pack get away to give yourself some room to run some clean laps and get a good laptime.
The grid in CTRA servers is ordered by your laptimes in previous races, so at the start of the second race you will be in the pack around racers of your ability.
Then it's just making sure you have good situational awareness. Making sure you know where those that are close to you are at all times, and giving way cleanly if you find yourself in a blue flag situation.
If you cause an accident always apologise and let your victims back past you even if this costs you position.
Don't get involved in silly arguments. (not always easy i grant you, but it gets you nowhere)
Race clean, ignore idiots(unfortunately there's always a few on whatever server), don't get frustrated if you get taken out a few times to start with, have fun, race some more
Enjoy!