As a general rule, I ascertain what is a complete transaction, such as purchasing of a permit on line, for filing a quarterly report, etc., that is one complete transaction a user would perform from start to finish.
Then I ramp up the users, going from 1 VU, 2 VU's, 5 VU's, 10 VU's, 25 VU's, 50 VU's, 100 VU's, 200 VU's, 300 VU's, etc.
After this I take the timing files and put them into an Excel spreadsheet, in which I can show transactions per minute plotted against times per each of the VU iterations mentioned above.
I end up with a a chart and graph of where the application has its point of diminishing returns.
Anyone else have a better way of how they present their findings?