Make diffuser oil using essential oil and a diffuser base. Use dipropylene glycol, safflower oil or sweet almond oil as the base, and then add essential oil to give the mixture a pleasant fragrance. For a light fragrance, use a mixture of 15 percent essential oil and 85 percent base, or increase the essential oil to 25 percent for a stronger fragrance.
For a savory smell, try using vanilla and chamomile essential oils, or a combination of the two. Oceanic and citrus scents also work well together; mix a few drops of each oil on a plate to create the desired scent. Note each oil's ratio in the mixture for future reference.
If the oil struggles to travel up the diffuser reeds, decrease the proportion of essential oil in the mixture. The essential oil is thicker than the base liquid, so it is more resistant to traveling along the reeds. Higher quality essential oils have a stronger scent, so less is required to create a pleasant atmosphere.
If the base liquids are not available, mix 1/4 cup of water with 10 drops of essential oil and a small splash of vodka. This mixture works in a diffuser, but it must be replenished more often as the vodka evaporates.