I put plenty of treats on the track and I don't give her too much at the end. We haven't done articles yet.
I haven't tired her out before the track, but I will do that next time and see if that helps. And age it longer.
25 minutes is still a pretty fresh track. You might try an hour.
Serpentine, articles, circle track (they start and finish in the same location), more food, tire her out a bit before you track, longer and more corners. Make sure the track is the reward and not the end so if you are using food there should be a lot of food on the track and only a tiny ending pile for the finish.
Longer, harder tracks can help especially with experienced dogs, but they can also cause stress and fatigue making the dog faster or hectic.