Select the objects to align, then click the object you want to keep in position (without shift held). This makes the object the alignment “master”.
Now choose “align centres”. The master object will remain in position and the other objects will move to be aligned centrally.
This method can also be used to align objects by left, right, top and bottom. Normally in these cases, objects are aligned by the leftmost, rightmost, uppermost or lowermost edge of any of the objects. By selecting an alignment master object, you have far greater control and can retain the position of this object on the artboard.
Found this tip useful? Find out how to align objects to the page in Illustrator.