Time to grind. Once I have laid down some good times I have a look at the replays from the others. I sometimes look at the number 1 guys, just to check that they are taking the same route. Sometimes they will have found a better way to hit a ramp, so then I start to polish my runs. The top in the world tend to be so much better at it than me that I don't check their replays for every track, just one or two. But, I always check the replays of those at the top of my friends leaderboard. It gives me a bit more confidence, as I know I can beat them on some tracks.
I used to go hell for leather, and at top speed. The trick is to master the low speed ones too, knowing where to actually slow down and take a ramp slower, so that it sets you up perfectly for a key ramp. Also, be aware that if you go with the throttle on down a ramp, you sometimes make a shorter jump off the end. Little quirk, but good to know. If you have gold on them all so far, you probably know most of the quirks. The only other tip is selecting the right bike, keep an eye on what the others use. And, on the replays note the controller moves that the good riders used. I was stuck on Trials Evolution on Dark City Run, until I established how the pros did it. Knocked 100 faults off my time by just getting one ramp sorted.