Manti gives good advice about clipping in and out on a trainer, so it becomes automatic for you. A few more quick tips about clipless pedals:
You can set the tension on most clipless pedals to make it easier or harder to unclip. In general, riders new to clipless should set the tension on the easiest setting.
Be sure to check the cleat on the bottom of your shoe from time to time. The screws on the cleat can get lose and make it tough to get in and out of the pedals.
Most pedals have a way to lubricate the system to keep it working correctly, check with your bike shop about how to take care of your pedals.
Unclip your foot and rest it on the pedal as you coast/brake approaching a stop sign. Some riders prefer one foot over the other, but it is good to practice with both feet so you are comfortable setting either foot down at an intersection. (You may have unclipped your "non-preferred" foot in your blog and when you went to stop and put down that preferred foot, oooops it was still clipped in. We've all done it at one time or another. In fact, that would be a great community discussion, "Most embarassing tip over at a stop sign, stop light, intersection, stopping situation...")