Looking for Techniques for Riding Uphill on a Single Speed
I ride both SS/FG and approach climbing hills much of the same way I would if I were on a geared bike with one very big exception...MOMENTUM. When on a heavily geared SS/FG I gain as much speed as possible going into the hill and push hard to maintain it throughout the climb.

Basic climbing tips: 


Slide back on saddle and drive heels through the bottom of the pedal stroke
If you need to stand, do so while minimizing body sway and unnecessary counterproductive upper body motion
Get into a rhythm - climb at your own pace
Stay upright to keep lungs operating at full capacity
Pull handlebars into your thighs as you drive pedals forward


Hope this helps!