Start with one very specific tea. Make as many servings of that one tea as you can so you become familiar with its every nuance. Don't muddy the study with various cultivars and seasons, locations, etc. For example, if you were to decide on a gaoshan, begin with the same producer for the same harvest/release.
For myself, I love the smell of gardenias and found it elusive but present in the gaoshan I began with. I could alter different things to pull that aroma forward. By the end of the year, I could do this consistently. I then moved to other teas and applied what I learned from that first tea. It ultimately resulted in an intuitive knowledge of how to get what I want out of teas I prepare. Eventually, there's very little thought involved. It becomes second nature.
HTH