I can't speak to leather production. I'm still figuring that out myself. But if I draw on my experience while working at a small clothing manufacturer.
1. On station one operation. So I imagine for you it would be a cutting station, a tooling station, a dying station, finishing station, etc.
2. Order Scheduling If you know you have 25 orders of the same thing in the same color. It makes sense to cut and make all 25 at once, even if 10 of those are going to another customer.
3. Standardize. If your bread and butter is from a single item make it the same way every time, using the same hardware and dye. Meaning instead of offering 16 colors and 4 colors or styles of hardware. Choose 1 or 2 styles and colors and make that your "standard" options. Anything thing else falls under custom and garners a higher price.
4. Time management: Make one or two days your shipping day.(s) Pre-schedule your pick up or have a set day for the shipping drivers to come pick up your items.... and prepare and pack the items for shipping have them waiting for the shipping service.
That's about all I can think of at the moment.
Good luck.