I can stand for a couple miles at a time. I use a low cadence, like 60, not a racer's cadence by any means! The way to get better at it is of course to practice. That said, I don't really ride out of the saddle much. I like to stand about 1 minute every 10, maybe only 30". Gives my butt a break and feels good, especially on long rides. Because my standing cadence is so low, I usually shift up a ring if climbing, or several cogs on the flat. I watched a bunch of Pantani videos, trying to figure out the trick to it. It seems that his technique was to relax the ankle as the pedal came up and then pull it across the top with his knee, then keep the toe pointed somewhat all the way around. That got rid of the dead spot in my standing stroke.
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