The easiest way of course is by totaling numbers of QSO per time slot, band and / or mode. You can display this in all sorts of nice graphs.
There is another way to do it, and it is one I really like: showing the actual QSOs mapped on the planet earth. This took quite some time as the N1MM logger we used during the contest does not log / retrieve the location of the station worked. Using HRD LogBook as intermediate I retrieved this data from QRZ.com.
Now with some minimal programming I was able to show the contacts plotted on the globe per time slot, per band and per mode. I made several maps with different segmentations of the data.
I liked this animation I made best - it shows our progress over time (with 1 hour increments). The colors of the data points represent the bands and the shape represents the mode used.