Short answer
You learn to recognise scent notes by first smelling individual materials, consciously naming them and then finding them again in simple and more complex perfumes. Comparing works better than memorising hundreds of notes.
Start with real-life references
For citrus, a fresh lemon peel is a better first reference than a list of molecules. For herbs, you can use basil, rosemary and pepper. For wood, you can compare cedar objects, pencil wood or other recognisable materials.
This way you build up a mental library before moving on to more abstract perfume raw materials.
Work by family
Don't learn ten completely random scents at once. For example, choose one week of citrus: lemon, bergamot, mandarin, grapefruit. Then flowers: rose, jasmine, orange blossom, lavender.
By smelling related materials side by side, the differences become clearer.
Use words alongside notes
Recognising a scent as "cedar" is useful, but analytical words take you further. Is it dry, pencil-like, smoky, creamy, sharp or soft?
That descriptive layer later makes it easier to understand complex perfumes in which the raw material does not literally smell like the natural material.
Top, heart and base are not a stopwatch
Perfumes are often explained with top, heart and base notes. That is a useful model, but evaporation is gradual. Materials overlap and influence each other.
So smell a perfume at different moments: immediately, after fifteen minutes, after an hour and later in the day.
Blotters are useful, but not everything
Use neutral test strips when comparing several perfumes. Write down a code straight away so you are not influenced by name, brand or packaging.
Then smell the most interesting options again in their real application. An ambient scent, for example, must also be assessed in diffusion.
Repetition matters more than talent
Scent memory grows through repetition. If you smell vetiver today and then not again for three months, recognition remains difficult. Regular short sessions are more effective.