Need more depth

I took advantage of some good light before dinner this evening to continue experimenting with some closeup photography. I continue to have a conflict between physics and the pictures I want to take. I am using a long lens to create the pictures and the configuration is forcing a very narrow depth of field in the image. This can be effective for some images, but I for these images I want the depth of field to be more than a few centimeters. I have been experimenting, with limited success, with various settings to overcome this limitation. I think the next step if to let go of the programmed settings and start embracing the manual settings.