The pyramid represents the primordial mound from which the Egyptians believed the world was created. The shape of the pyramid is thought to represent the rays of the sun shinning down, which makes a lot of sense because the Egyptians believed the sun to be a god and therefore the mummy within the pyramid is surrounded by the rays of a god.
Another belief is that the pyramid was a vessel for the mummy to enter into the afterlife and therefore live forever. The entire Pharaoh's prized possessions where placed in the pyramid in order for the Pharaoh to be able to take them with him into the afterlife. For this meaning and the above one if you are looking for some symbology in your pyramid tattoo you can use it to portray what you hold most dear.
The pyramids are also believed to represent a stairway to heaven and when a pyramid was completed then the Pharaoh was truly a god ready to ascend to heaven. This symbology can be used in a tattoo as your success thanks to the hard work (building blocks) that you have gone through to achieve your final goal.
Most Pyramid tattoos are combined with other symbols or hieroglyphics in order to portray the message they are trying to get across as well as to make the tattoo look good.