The command "show dot11 associate" is a very useful command summary. This command will show me the following:
1. Who/What clients are trying to associate and what SSID are being used;
2. How many clients (successful or not) per radio;
3. How many clients (successful or not) per SSID; and
4. How many clients have not successfully associated/authenticated.
Successfully associated/authenticated have IP addresses and under "State" it should be "Assoc". If you add the client MAC address after the "show dot11 associate" it will show you alot more detail, such as:
1. If association has failed, what could be the cause;
2. Duration of the client associated to a specific SSID;
3. Signal strength and Signal-to-Noise-Ratio (SNR); and
4. Data traffic to and from the client.
Hope this helps.