This is something that comes up quite often.
Personally I have announced the Cake Cutting followed by the First Dance just after dinner which is then followed by the Bride/Father.Groom/Mother and lastly the Bridal Party Dance. However more recently I now announce the First Dance & Cake Cutting immediately after the introduction of the Bride & Groom.
The logic behind this is:If the cake is being used for desert then the cake cutting must precede dinner so as to allow ample time for the cake to be cut and served after dinner.
Secondly having the First dance after the B&G’s introduction has the advantage of receiving maximum attention from the audience. This is when their attention span is at it’s highest, especially when since have not eaten yet and have been sitting around for 1-2 hours.