Mistake analysis, is about looking back and seeing which moments got the better of you, when you should have slowed down, looked up, made sure of a compass, come up with a detailed plan or basically done anything to kick the butt of that particular moment.
A common mistake is looking at the outcome of your mistake as the mistake, rather than as the stupid, idiotic running around in circles, crazy man routine you done after you've let yourself down further back in the leg. To embarass myself I have a couple of examples from the weekend below (you can't make mistakes like these and beat Bill Edwards of sanddune terrain no matter how fast you run the rest of the course.
Leg No 3: Heading out of 2 my bearing was only very rough. I hit the track and raced over it trying to find a good path through the very rough terrain. I didn't give myself a chance. I was running along a slope, but I actually thought I was further to the right, running along a parallel slope, hence when I came to a low point in the ridge I headed hard left, only swerving back right when I saw the road fast approaching. The latter mistakes in the leg are there for your amusement but arose largely because I had lost all confidence in my angles and exactly where I was. The major mistake that wrecked the leg for me was very early on crossing the track and not making 100% certain at this very easy point. I had a chance to correct myself at the 2nd x but again failed to do so. I got mastered by the moments.
Leg No 17: I had decided in the route choice before clipping 16 and creamed it down the hill to the clearing and round the track, swinging wildly onto the ridge, I made connection with it briefly, but thought that the control was a bit further off the ridge lines direction than it actually was. It turned to custard out there in the flatter stuff and my recovery was poor. Again I made my mistake the best part of 200 metres from the control circle where I lacked the discipline to hug the linear feature and work out a clear plan for attacking the circle. The mistake wasn't where things started looking uncertain within 100metres of the control. It was where they felt so easy and in control where I have marked the X.
If you are into it, have a look at a recent map or two and try to identify where you really made your mistake, not what the outcome was. When was the moment that you could have put a plan in place or exercised some discipline to prevent the mistake from happening?