This one is extremely useful. Often you find that you’ve been charged by some company from your bank account, but you forget which site it was. If your bank transaction shows a debit on a particular date, you can search your email for any order confirmation mails.

In Gmail, type the following to search between 10 July to 12 July (i.e for 11 July):

after:2012/07/10 before:2012/07/12[/code]

i.e the general format is:

after:yyyy/mm/dd before:yyyy/mm/dd[/code]