I cant remember ever scoring a round even to be honest. I try to subjective with 4 main criteria

Control of the ring
Aggresion
Volume
Effectivness

But this seldom works. It is boxing afterall crazy things happen in that ring.Boxers having haircuts in the mid-rounds .

I tend to just go with the flow and weigh up every round how i see it.

I would score it a draw if both fighters stood feet planted in the centre and landed exactly the same amount of punches with the same force.Otherwise there's always something you can give to one fighter.