There are 2 ways to do this. The first way is to go to the golf course just above Montano Plains. Then just drive around and pull off some combos, like drifting, getting air, kangaroo jumping, etc. Don't take a really fast car as its easy to flip it over, which will take away your combo. At times I was pulling in 50000 in a combo. I had finished all the festival events and street races, I was level 48 and it took me about half an hour to get to level 1. The video below shows this method. This is not my video, all credit to the original maker. The second way is to keep driving around the Horizon Festival Circle and drift. I found this method quite hard as I kept crashing into other cars. The video below shows this method. This is not my video, all credit to the original maker.