Use a carrier oil (like olive, sweet almond, fractionated coconut, or jojoba oil) to dilute your essential oil when applying to skin. I have seen these carrier oils sold at my local grocery store in the health and beauty sections, on Amazon and at Natural Grocers. Diluting isn’t always necessary, but it's best to start that way to ensure your skin, nose or head aren’t too sensitive! I didn’t listen and as a result I was getting dull headaches because the oils are so potent, and I wasn’t used to them yet. Some people refer to this as detoxing because the oils are pulling toxins out of the body. Using YL oils has caused me to hate the smell of chemically infused products, especially bathroom spray, candles and body wash. They smell so fake to me now and I will never go back to them...Ok back to safety :-)
Store your oils in a cool, dark place to keep their compounds from altering.
Keep oils out of your eyes and ears. If they accidentally get where they shouldn't go, use a carrier oil (not water) to rinse it out. Oil and water don’t mix, remember!!
It's always wise to start slow and small and consult a doctor well versed in oils before use.
Always put citrus oils in glass, paper products or aluminum. Citrus oils (lemon, lime, orange, citrus, grapefruit, etc.) are incredible at pulling toxins out of plastics. If you are going to drink water with EO in it, you don't want to also drink plastic, even the BPA free stuff can still have toxins pulled out. Yuck! Only medical grade plastics are safe.
Check the oil bottle before ingesting an oil to be sure that it is labeled as a "dietary supplement."
Always heavily dilute with a carrier oil for kids and babies, never straight out of the bottle. Only diffuse around newborns. We never apply topically until our little ones are at least 6 months old, and we always dilute heavily! Pregnant or nursing moms should do their research before ingesting or applying oils just to be on the safe side!!
This are just my tips. I'm sure there are many more. Do your research!!