Fabien Barel did an interview a while back about speed and flow. He said something along the lines of inexperienced riders pedal to be fast and experienced riders pedal less and flow. Makes perfect sense. If you flow the trail all relaxed and smooth you'll have lots of energy for the punchy climbs. When I was training in BJJ I made the classic 'white belt' mistake of starting all amped up and tried to muscle my opponent around. This lead to me gassing out and being beaten. Translate that to bikes and its the same thing. Try and relax and be methodical about how you ride.
^^^This.
This year when I entered the local mtb series focused less on going fast all the time. Put effort this time into dying to be more smooth and go with the flow. Less effort on hammering to make up for bobbles and such. Better results with less effort.
One thing I started trying coming into corners is stop pedalling before the corner and let the bike slow itself down. Braking way less now.