Large kitchens have enough space for you to be able to adjust the placement of your oven as well as that of your refrigerator. Ideally, refrigerators should be situated at least 9 inches away from an oven; this distance is enough to help lower your utility bill by preventing the heat from the oven from forcing the refrigerator to work more, and vice versa. Small, apartment-size kitchens, however, may not be large enough for you to be picky about placement. If this is the case, put something between the refrigerator and the stove to help insulate.
Foam insulation will absorb heat from one side and cold from the other, helping to keep temperatures from equalizing between one side and the other. Purchase foam insulation from a hardware store. Cut it to size with a serrated knife so it doesn't poke out beyond the appliances. Slide it between the oven and refrigerator.
Place a dishwasher between an oven and a refrigerator to provide some distance between the very hot and very cold appliances and to utilize the space efficiently. Insulate between the oven and dishwasher as well as between the dishwasher and the refrigerator.
Most kitchen, even very small ones, have a small cabinet you can place between the stove and the refrigerator. For energy conservation, such a cabinet should be at least 9 inches wide. It can fit flush against the oven but should sit several inches from the refrigerator.
Depending on the type of refrigerator you own, you should leave some empty space between the oven and the refrigerator to accommodate for door swing. Some very large refrigerators can need up to 9 inches for door swing clearance. Change the direction that the refrigerator door swings if doing so frees up more space in the kitchen.