I just watched some trials videos and i noticed guys like Toni Bou always have a finger on their front brake at all times when they are riding. I was just wondering if i should be do this? Thanks

Its all a matter of preference really. I ride that way as i prefer it as it gives me better control over the bike at all times.

I also ride with my finger over the front brake, I did try not to do it once thinking it might give me better throttle control. I ended up all over the place haha. I personaly also much prefer To cover the brake to keep control.

I cover both the front brake and the clutch. Sometimes on big steps I will take my finger off the front brake to really get a "fistfull" of throttle, but I am trying to do big steps while covering the brake.