Interesting topic... I used excel to keep track of test scores and performances back in 2003 when I was preparing for an MBA entrance exam. It was a crude sheet (I didnt know what excel is and what all it can do, I was just using it as a fancy notebook)
But essentially it was SWOT analysis. Here are some ideas for you based on my experience back then,
Lets say you are doing swot analysis of your on job performance.
> Create a simple table layout where you record your experiences. Include columns like date, what you did, what worked, what didnt, where you could have improved, what worried you etc.
> log your performance details every day.
> Once every few weeks spend an hour or two with the worksheet to see how well you have performed and where you can improve.
> Prepare SWOT based on all the inputs. You can easily find strengths by looking all the things you did well etc...
Based on my limited management experience, SWOT is more of a feel thing than process thing. So it involves a lot of introspection, ideas and qualitative judgment. Excel is probably not a good tool for these kinds of things..
just my ideas..