I read this tip at www.personal-assistant-tips.com (a great reference site) the other day for when you're handed a piece of paper and told to 'look after it until the end of the month' and loved it - I know whats going on my next stationery order:

Invest in a concertina folder, labelled with the days of the month, then ask your boss to give you any papers that need to be brought forward.

For instance, if your boss has just sent an email which needs to be followed up in 10 days time, ask him to forward a copy of the email to you, stating when he would like it brought forward to. File the email in the appropriate slot in the bring forward file. Alternatively, he could write the words b/f on a hard copy and the date it should be brought forward to. Check your bring forward file every morning and leave the appropriate brought forward document(s) in his In-tray.

What a great tip - do you do something similar for your boss?

From: http://www.personal-assistant-tips.com/Organise-Your-Boss.html