Technique = are you regular or goofy? This is like the setup for skateboarding or snowboarding. Once you find out what is your leading foot, keep that sucker clipped in at all times
My SPD's clip and unclip with ease, and trust me that they do not unclip unless I need to. I can even unclip both of them at the same time - usefull skill on a fixedgear - to reclip them at mad speeds.
Practice a little more, and adjust your clips so unclipping becomes natural and instinctive. It is also advisable to practice pedaling from a start with only one foot, another usefull skill that pays off in traffic.