Always store fuel in a tightly sealed, approved fuel container. It should be stored in as stable environment as possible (avoid drastic changes in temperature as much as possible as this encourages condensation and speeds degradation of the fuel.) Also avoid direct sunlight.
Although many manufacturers suggest the use of fuel stabilizers, we generally do not recommend them. It is often difficult to get the proper ratio when mixing with small quantities of fuel. We have found that if it is blended too strong it can cause more harm than it prevents.