On the Facebook/smelltraining page there was a recent question about smelling from the bottles of essential oils vs. smell training from jars as is described here on the website. I want to describe here a bit why I think jars are superior to smelling from the bottle, using perfumer's strips or using drops of oil on cotton balls.
The jars described in the instruction sheet are 30ml amber glass jars. They are small enough to fit in your pocket and not be heavy, but large enough for you to get your nose into when you take the top off. Why is smelling from jars different from smelling from an open bottle? Opening a bottle just allows a small amount of the volatiles (smelly air) to escape. You are limiting the smell by the small opening in the top of the bottle.
The air in the jars on the other hand is very "smelly", because the bottom of the jar has an absorbent disc that has been moistened with drops of the essential oil. Put your nose into the jar and get an extremely strong scent. If it is too strong for you, use less oil or don't put your nose so close. If you are just starting out, you will appreciate having a concentrated smell to try--you will be absolutely sure that you are getting a proper dose.
For the absorbent discs, I use high quality water colour art paper. You can easily cut it with scissors to the size of your jar. Don't put cotton balls into the jars. The essential oil will go off faster. Why? Cotton balls are made up of lots and lots of little filaments that can harbour bacteria. It's the same principle as old fashioned mops that so quickly got smelly vs the microfibre mops that have short filaments.
Depending on how viscous the essential oil is, 2-3 drops should be sufficient.
Perfumers' paper strips, like you see at the fragrance counters of department stores, are meant to be used with alcohol based perfumes. Perfume is very volatile, and the alcohol evaporates quickly from the strip. The alcohol in it makes it a very different experience than smelling essential oils (which are oil based, of course). If you are using strips, and you are "nose challenged" already, you risk touching your nose to the strips, in an effort to make sure you are really smelling them. With the jars, your skin is always well away from the source.
Keeping your bottles of essential oils in the fridge is also important. They keep better at a lower temperature, but light is their real enemy. By keeping the essential oil bottles in the fridge, and using just what you need to make up a jar, you can make more economical use your your essential oils. Fresher oils = a more vibrant smell experience.
I hope that is useful for you! Good luck with your smell training.