I am most concerned about my pedal technique when I am climbing. With only one gear you can not down shift and spin fast up hills. At a lower cadence the angle that your feet are positioned at can make it much easier (and faster) to climb.

Your crank arm is a lever to which your feet apply power. This power is most efficiently applied when the pedals are at the 3/9 o'clock position because you are pushing on the lever at a 90 degree angle. At this angle all of your energy is going into the drive train. The time you apply the least power is pushing straight down at the 6 or 12 position. Here all of the energy goes into trying to stretch/compress your crank arm.

By consciously adjusting the angles of your feet during the pedal revolution you can keep the angle between the pedals and crank arms closer to 90 degrees for a longer period. The most important parts are thinking about "scraping" the ground with your toes as you past the bottom of the stroke, and angling your toes upwards as you pass the top of your stroke. With practice this technique will make it much easier to climb on a single speed.