Hey! I'm also studying Burial Rites next year, and have also annotated the book as it was a part of my holiday homework.
When I annotate books, I usually like to get a list of themes and other things from my teacher of things I should be looking out for specifically. For Burial Rites, my teacher gave me the themes Love, Control and Agency, Truth, Loss, Moving Forward, as well as Conventions such as Symbolism and Motifs. I then assign each theme/convention a colour and I go through the book from the start to the end, and which ever quote or passage of the text I think is usuable for an essay and is relevant to any of the things I'm annotating, I'll highlight it in that colour and write notes in the same colour pen on the page close to the quote (Burial Rites has narrow margins so I used sticky notes.) I'm known at my school for going overboard with my annotations, and my books end up looking like colouring books, but I can definitely say I am always prepared for essays and have my quotes ready to go! If you want me to upload pictures as examples I can definitely do so!