Not sure if this will help but...
For information you really do want to remember for ever, try to put each bit of information in context. Visualise yourself using the information in the air. Use all the memory tricks you can find to keep the information distinctive and visual.
For information which you just can't visualise EVER needing in the air (e.g. bits of the ICAO convention!), try planning a presentation on the material to a third-party (another CPL'er). Ideally, you would actually give the presentation, and also answer questions on the material at the end. Make yourself an expert in the material for just long enough to pass the exam. Then forget it. Chances are you won't, and who knows, the £1M question on Who Wants to be a Million might just relate to the Chicago Convention
)
Best wishes