You can change the time increments shown in your Outlook calendar to allow for smaller more detailed calendar entries. This will work in Outlook 2003, Outlook 2007, and Outlook 2010.
It is very easy to accidentally drag and drop items into a new location without realizing it (i.e. an e-mail folder in Outlook). If you turn on the ‘ClickLock’ feature on your mouse it can help eliminate any accidental errors. When ‘ClickLock’ is on, you have to click a second time to drop the item in its new location. ‘ClickLock’ settings are different in Windows XP and Windows 7, see the appropriate documentation and video for your operating system.