I thought it might be my ink pad, so I switched to Versafine. I still wasn't pleased with the image quality, so I switched to glossy cardstock. Then I remembered to read the back of pad. It says, "Fast drying oil based pigment ink for uncoated papers (drying time varies depends on paper)." Since glossy paper is coated, this made for slower drying time. It gave a good black image, but smeared when I tried to use it.
I pulled out my Stewart Superior Document Stamping Ink. This is the company that makes Memories ink and it would probably work well also. This ink gave me a nice dark black image on my glossy paper. I will work on assembling some cards today.
Lesson for today: Choose the proper ink and paper carefully to get a successful image.
Another tip: I find I get a better image by standing up when stamping to get an even pressure over the surface of stamp.
PS: Check out this tutorial on the Stars & Stamps blog. This is a great explanation of stamps and stamping techniques.