The water pressure in my kitchen is almost gone. What should I do? All the other pressure in the house is fine.

If every other faucet in the home has good pressure I'd recommend taking apart the kitchen faucet starting with the aerator. Make sure the aerator is not plugged since it catches most scale and debris. If you still have not pressure it is time to close the main and remove the valve stems. Clean and/replace any stem that is plugged. While the stem is removed have a friend open and close the main for just a second while you hold a towel tightly over the openings. This will flush out the valve body and pipes. If this has not cured your problems come back with what you noticed and we'll take it from there.