Check some eBay vitals, gather some data about your eBay business!

Check your Gross Merchandise Sales each Week

Total Listing Fees for that week? Are they too high?

Payment System Fees

Is your average selling price increasing or decreasing? (GMS/ No. Itms Sold)

Then with this simple calculation work out your Conversion Rate for that Month

Number of Items Sold/Number of Items Listed= Conversion Rate

This will give you a percentage of how many successful items you had close in relation to how many listings.
The average CR (conversion rate) on eBay is 50%, go below this and you need to re-jig your listing strategy as you are listing too many items, or listing them to the wrong category, in the wrong format or at the wrong times. There are so many variables on eBay and you can keep a weekly check on your vital signs!

Each week check on your profit margin for positive and negative trends.

If you happen to be a channeladvisor customer:

You will get a comprehensive report at the end of the week and month! You need to check your vital signs each week to avoid pitfalls or fees spinning out of control!