The idea is to stay lit on fire through the entire run.
There are only 2 ways to extinguish yourself, which you need to watch out for:
1) The beginning pipe. Avoid it by waiting in the start gate for 3 seconds.
2) The "puddle" that's about 15-18 seconds in the race. Make sure that you hit, and go over the large drain pipe, to flush the water out.
Now, you just need to string together a run, while lit, without faults in a fast enough way that you don't explode. View the video for what I found to be the most reliable pathway around the track.
View here: