Dude, first of all, you have got to relax. The onli reason your car flips over is becos your goin to fast.
At the start of the race, try to stay behind the group, alongside cesar's car. your opponents always crash into some oncomin vehicles. by the time you reach the large road along the beach, you should be in the 3rd or 4th place. Floor the accelerator and try to avoid the traffic. 4 me, i drive on the sidewalk. it gets me 1 or 2 stars but i don't care. once you turn rite onto another road, drive fast and hard. up ahead on the race course should me some reli quick turns, slow down and take each curve carefully but quickly. you don'y have to worry abt the others takin you over. if they do, don't panic. jus drive carefully. once you are at the pier, floor it. tis is wher i use my nitros. but the best advice, treat you car rite. i spent like $20,000 on my Blade. i've finished the entire game and i still have that same car from the start. NO JOKE!! hope tis helps.