Nothing more than a crush mode and destruction and smashing

I can't figure out the best way to maneuver the road and keep from stopping. I beat a few Showtimes but I don't understand the best ways to hit a veicle like landing on it vs boosting into it, vs just clipping it. Also does going uphill or donhill seem to have any effect on momentum? I can't figure out how to keep the momentum I need to go as far as I want to flip/crash to achieve the records I need for the in-game license requirements.