Before doing the 10-vehicle race, do the speed challenge and time challenges first. They build up credits to buy upgrades. After the first 20 minutes playing, I was able to become #1 out of 10 on the first try! Also, if steering too sensitive, tilt your iDevice a little more VERTICAL (top edge pointing more directly up) while steering. That will make steering easy and less touchy.
mdrejhon about AG Drive, v1.5.0