Humans seem to be hard-wired to move from left to right, top to bottom. It seems like a basic literacy concept so formally in-grained within us that it can be difficult to break out of this. In a lot ways moving from left to right, and top down is good. Personally, I get the most from my reading by starting in the top left corner. In fact, when I read a new piece of music I start there too. That expectation is so universal that we don't have to tell people where the beginning of a tune is. But here is the rub: there is no rule in transcription of where you begin. Still, many transcribers start at the beginning of a solo and work through chronologically.
I would like to offer a different strategy. Think of transcribing like completing a crossword puzzle. The crossword puzzles begin with a list of clues. As one goes through the clues, the puzzle fills in, revealing what some of the harder words might be. In transcription, we are dealing with phrases, licks, and musical gestures rather than clues. Learn the phrases that are most straight forward first, and begin to fill in the linking material as you transcribe. This is especially useful if you have been doing the kind of prep-work that I suggest in the last post. Click Here
Putting this in context, let's say that you are struggling with a specific phrase, but can at least figure out that it ends on a concert Bb that lands on count one in measure 11. Great! Write it down. Perhaps you also hear a triplet on count three of measure 10. Fantastic! Write that down too. Now, you notice that triplet is a D-Eb-D above the concert Bb that ends the lick. Through some experimentation, perhaps you also learn that there is only a few ways that triplet would logically connect to the Bb and you decide the one that sounds and feels the most natural is to connect them chromatically with a Db and C