Generally speaking, I seem to sit through most of my climbs. When others on a ride are standing, I remain seated either throughout the climb or for a longer time before I stand. Once I stand, I have a fair amount of stamina to keep churning, but I don't feel that I have much acceleration or excess strength. For example, compared to this guy with whom I ride pretty frequently, I'm a better climber, but it's because I'm stronger while sitting. If we're both standing, he powers past me.
For a while I thought this was about learning to get the gearing right while standing, and that's definitely part of it. But recently I've concluded that it's partly because I simply don't feel that strong while standing. Standing calls on different muscle groups, with less emphasis on the quads and more emphasis on, well on what? the calves? the glutes? What else?
Anyway, I've realized that I need to force myself to stand more on climbs so that I can get better at it, and that I need to spend some training time specifically doing standing hill climbs.
Have you folks got any tips or wisdom about the art of climbing whilst standing? How about foot position? Do you try to keep your feet horizontal? I find I have a tendency to point my toes down while standing, and I'm pretty sure that that's wrong and makes it harder to pedal circles.