If your Sphero is glowing a solid bright/ white blue and doesn't respond to shaking, attempts to pair, etc., it is most likely connected to a previously paired device.
To resolve this issue, make sure that all bluetooth devices you could use to connect to Sphero (smartphones, tablets, iPods, etc.) within 50 feet are turned off or have bluetooth turned off.
Place Sphero in the charger and hit the button on the side of the charger, this should hard reset Sphero.
Now Sphero should be able to blink its 3 color code and you should be able to connect to it with your desired device.