Just pay attention to the prompts for races and upgrades and get to know the map well enough to use good hiding spots during pursuits. Otherwise you'll need to keep an eye on the mini map after boosting away and stay on th emove to avoid th ecop icons spawning in.
Use of upgrades is pretty simplified, straight forward and self explanatory for the most part. There's not much to the game really. It practiucally plays itself, has little if any learning curve, and gets a bit boring and repetiious. You basically have to go back and keep doing the same races over and over to win upgrades for each new car you acquire.