based on Feedback sent by a lot of power users on Google+, Google engineer Bret van Zuiden released an update that makes everything easier. Reordering your circles is now as simple as drag and drop. To reorder your circles simple drag and drop the circle in the order you want. Once that is done it will stay in the same order across Google+. So now you do not need to waste time finding the right circle but important circles will stay in the way your placed them in order.

This order will help you when your viewing your stream, sharing or adding a person to your circles. The list will remain in the order that you specify. Even when adding people to your circles, all your circles will appear in the order you set. makes things easier and cleaner.

How to reorder your circles
1. Click on your circles tab in Google+
2. Click on the circle you want to move
3. Drag and drop it to the position you want.