When I first started playing this game. I would pick the slowest car and do laps of all the tracks on an empty server.
this helped in 2 ways
1. I got a rough idea of all the tracks quickly
2. I managed to get some PB up on the wall
then I moved up to the next car and did the same again. this meant that not only did I get to try all the cars and all the tracks I also ended up with PBs for all cars and tracks. This then gave me something to aim for the next time around.
Another goodie and I was very lucky with this was get on a server with 1 or 2 ppl on it and try and follow them. I left the pits right behind someone was far enough back to see what he did and I followed him for 5 laps. This helped me so much that if I have a new setup I join a server watch to see who is going round quickly and then sit on the start straight (out of the way) and wait for them to come round then jump in behind and follow.
Most of all enjoy..its a great game.