Nah look Op, winning races is easy and has little to do with luck.
Between catchup and slipstreaming the best tactic is to simple take it easy at the start and avoid all the demo drivers.
Don't drive like a psycho and don't over commit to corners.
After that simply slip/catchup your way to a nicely timed lead.
The key is control not speed.
If you do get pummeled just recover as quickly and nicely as possible.
If your car is a wreck then hold Y and respawn and it will be like new again.. although then you have a race on your hands.
Also it helps to look at the course beforehand if you are not familiar with it, noting the distance, laps and corners or straights then selecting a car accordingly.
Once you have a few wins buy or steal cars in each range and pimp them up a little to give you more of an edge.
Invest money in things that help speed/control only... don't waste money on flash unless your into that.
Sorry to say it man but this is just a case of L2P.