Transcribing Tip - Bookends
When working on an exceptionally difficult/fast lick, it can be a good technique to grab the book-end notes first.
Let's use the opening lick to Little Walter's "Off the Wall" for example...
If you focus on the the first note of the ascending passage you'll hear that it's the 2 draw. The next long-held note is 5 draw and then the last note is a 4 draw.
If you listen carefully, you'll hear that there are two notes between the opening 2 draw and the long-held 5 draw... so you would then experiment until you figured out which two notes sounded the best... in this case the 3 and 4 draw.
There is one note between the long-held 5 draw and last 4 draw. This only leaves two possible options... a bend on the 5 draw or 5+... in this case it's the 5+.
So, start with what you can hear and then count how many notes are between, and then experiment until it sounds correct to you.