The Gemini Project is an international partnership of Canada, the U.K., the U.S., Chile, Argentina, and Brazil, to build two 8-meter telescopes, one on Mauna Kea, Hawaii, and one on Cerro Pachon, Chile. The telescopes are to achieve an unprecedented combination of light-gathering power and image quality over the infrared, optical, and ultraviolet spectral regions observable from the ground. The key scientific requirement for the telescopes is that images at 2.2 microns delivered to the focal plane are not degraded more than 0.1 arcseconds over an hour's integration. In addition, these telescopes, in particular the Mauna Kea telescope, should be capable of reaching infrared emissivities of between 2 - 4% in operation. These requirements present special challenges for large telescope builders. To address these challenges, the Gemini project regards the entire observatory as a system. All aspects which may limit performance are tracked through the use of a systems error budget that includes the enclosure, telescope structure, both mirrors, control system and the instrumentation. This paper will highlight the meniscus mirror support system, the control philosophy to reduced wind buffeting and strategies to reduce thermal effects such as mirror and dome seeing.