Dropping weight can be done in several ways.
Adding work (lifting and/or conditioning)
Cleaning up a dirty diet
Or a combo of any of those.
If you need some help dropping weight, you'll have to give more information. If it's a small % of your total weight it can probably be done with water restriction before a fight. If it's more than water weight, you'll need a combo of the above.
I'm more for doing more work (to a point) before cutting calories. I feel it allows more strength to be saved.