I passed and here is my two cents:

1. Read mike Griffith book twice.
2. First step to acquire 21 contact hours. I was looking some interactive live classes and lucky to found 360PMO.
3. Took free practice exam from the list.
4. Questions on Scrum: sequencing the event, ceremonies duration, pillars, artifacts, ceremonies, roles.4-5 questions on XP, lifecycle, engieering practices e.g. pair programming, contineous integration, spike, etc.. 2-3 questions on Kanban, 4-5 quesitons on Agile manifesto. 2-3 question on velocity, burnup/burndown2-3 on retrospective actitivie and 3-5 questions on Lean, reason of playing planning poker in estimation, acceptance test vs. definitiation of done.
5. Did not purchase any practice exam, except 360PMO which comes with my training. If you take 360 PMO full-length practice exam, you will get fair understanding; it is pretty close to real.
6. Make sure to gain good understanding on various Agile practices, user stories, product backlog, prioritization, estimating in point vs. Estimating in hours, MMF, VSM, MVP, TDD, ATDD, cumulative flow, WIP, osmotic communication, wireframes, etc.

the exam is easy (compare to PMP), but the trick is study right contents and give is a right time. I wish you all best of luck in passing ACP