Oil Burners
Just put a few drops in with water and leave a candle to burn. You will notice the fragrance within a few minutes.
Air Fresheners
If you have an empty spray bottle, just rinse it out. Then re-fill with a little cold water an a couple of drops of essential oil of your choice. It will scent the room, without the cloying taste in the back of your throat traditional air fresheners can have.
Massage
Benefit from the massage, and from the scent! Mix a few drops of essential oil with your carrier oil for a noticeable effect.
Bath
If you just use the scent, you may experience a reaction. Try mixing with a carrier oil, as with the massage, and add a tiny amount to your bath water. You will have the scent and the moisturising effect of the carrier oil.
Vacuuming / Hoovering
Here's a clever trick if you have a bagless vacuum cleaner. Take a quarter of a square of loo roll and put a few drops of essential oil on it. Put this in the dust collecting part / drum / bit you empty. Every time you vacuum you will smell the oil.
Ironing
Ironing can be a fairly dull job. You can make it more appealing by putting a drop of essential oil into your ironing water. This will make your ironing smell lovely, and there will be a subtle smell on your clothes.