Beating other Racers
In order to beat the other racers go to the garage once you have amassed enough cash and buy the fast car in there. once done, max out the performance and you should have no problem beating the other racers in LA. Using your Car-Tricks
When you think you may be loosing use your advantage like your agro or something to blow the other cars away before reaching the finishing line. then you got that smooth sailing all the way in. Get a Motorbike to Beat Andrew
If you need to build experience on a motorcycle, then you would need to buy the Kawasaki and max out the performance. you may have to ride out the whole city in order to race Andrew since he's sick of racing 4-wheelers now.