Ask HN: Transferring responsibilities at work

I recently gave my employer notice that I will be leaving to start a new job. My responsibilities need to be picked up by other people in the office and I am looking for ideas on how to approach a successful mind dump.

My natural instinct is to write a word document/create a pdf. I am curious if anyone is aware of a site/service/program to help me organize my thoughts.

I would like to hear about your experiences taking over someone elses responsibilities. What did the person before you do well and what did they do (or not do) that made your job more difficult?