If you're new to thinking about scents, you will have a hard time picking out notes and understanding how to analyze your reaction to a scent. That improves the more you smell things and spend time thinking about what you're smelling. Sniffing something while reading a bunch of reviews of the scent will help you. I wouldn't worry too much about being able to discern individual notes - fragrance is meant to be experienced as a whole, not as a collection of ingredients.
Its normal for you to detect your own fragrance only intermittently throughout the day. If you are exposed to any scent continuously, olfactory fatigue will cause you to stop being able to perceive it. If you are spraying with the expectation that you will smell your scent clearly all day, all that will do is deaden your sensitivity to it, and annoy the hell out of everyone around you.