Saying that, just posted an 18m score, pretty happy with it. Watched a view high scoring videos and changed from using the right stick to using the buttons, I definitely feel a lot more in control of my tricks now.
I've learnt to basically get tricky within the first 2 jumps of Bulldog if you veer right at the start, you need it by the first rail. From there just alternate my special with some double tap combos (Circle Square, Triangle Circle etc) and don't rush down the mountain. Also, avoid the ravines! They fucking suck and there's no opportunity for high scoring to be honest, and getting out is a pain. Keep an eye ahead of you at all times, when in the air to see where you're going to land, where you next jump is and if you need to butter to keep that combo inbetween. And don't stop tricking! Even on flat areas, if there is space to jump and do a few tricks, do it. It's not a race, there's no rush, bag some points!