If possible, review your notes from each usability testing session immediately after you finish a session and before the next participant comes into the lab.
You can use screenshots of the website to quickly mark the elements of the interface that were problematic or highlighted positively. You can also use post-it notes to jot down the key usability issues/pain points and the positive experiences the user encountered.
This quick exercise helps us digesting the data we collected in each session individually, when our memory is still fresh in mind and facilitates the analysis process later on.
Ideally, invite the developers to observe the usability testing sessions so they can see the problems first-hand and start solving some of the obvious issues before the written report is completed.