The key is, IMHO, relaxation. Let go of muscular tension, meaning, sitting down and relax.
Once you can let go of muscular tenson in your back and lower back, you will find that your sense of smell gets better. There is a reason for this, but I leave it to your own intution to find out why.
Then open the oud oil bottle, first just uncap it. Sniff the bottle with the applicator stick still sticking in the oil. Draw a deep breath and then close your eyes. What are you smelling? are there spices, sweetness, herbalness, chocolate?
Or smething off-putting, such as gasoline, burnt rubber,; an overwhelming barnyard (some people love barnyard, to others it´s annoying!) ?
Then take the stick from the bottle, and smell that too. Stick it back into the bottle, and close yes again. Ask yourself again, what notes are you smelling -fruits, florals, wood, smoke?
Lastly, apply the oil from the stick onto your wrist or the back of your hand. Put the stick back into the bottle, close the bottle and place it away.
Then lightly dab your hand with the oil against the other hand -- either wrist against, wrist, or back of hand to other back of hand.
Or dab some oil lightly on your neck.
Again, smell and try to decipher the scent. Take a sniff every few minutes. and have a piece of paper and a pen ready, so you can write down your impressions.
I usually do this in the evening, when I have spare time, after a session of meditation (or even during meditation); and sometimes I lie down on a couch to relax better and allow my thoughts wander.
It has happened that I was passing into a waking dream --
--or simply dozing off into the most refreshing sleep imaginable ;-)