are you diying these yourself

The very best way would be to strip, re-stain and refinish. It is not expensive, but takes a lot of time and a lot of work - I am doing mine right now, though not darker. You could check into seeing how much it would cost to have done.

I have seen on the Internet tutorials where people sand the surface and use General Finishes Java gel stain. This does not require the total stripping. I am not sure of how good these results are in reality. Others have sanded and applied Miniwax Polyshades in a dark color - again I am unsure of the reality of the results - both the Polyshades and the gel stain have the potential to look like an amateur job because they don't really re-stain the wood. Gel Stain and polyshade tutorials can be found online. To get the best wood look, I would consider a total refinish.

From the picture, your cabinets look very nice, so consider carefully. Test any ideas out on the backs of doors - preferably ones high up and rarely used.

I have stripped and refinished a few small pieces of furniture, I found it messy, smelly and ... Well,,,, time consuming. I applaud anyone that tackles doing their cabinets but I personally would live with them until I could afford to have it done for me! Just so daunting.

We often tone the cabinets of our customers who want to go darker. We warn them they will lose some of the grain but they don't mind and we get good results.