Go to Tools in the task bar and then Customize. Once you are in the Customize menu, go ahead and click on the Commands tab. From here, you will see two lists. The one of the left contains different categories of commands, such as File and Edit. On the right, you will see the list of commands for each selected category. At the bottom center of this window, you will see a “Keyboard” button, which you should click. This will open a second window much like the last one. Again, it will have the category and command lists, but now you will be able to select a command and then in the “Press new shortcuts key” bar you will be able to enter a new command key combination.
For example, select the File category and then the Save command. Traditionally the Microsoft Office, and by inclusion Word, command for this is Control and S. Click into the box and press Alt and S. This will show up in the box, and then you will be able to press the Assign button in the lower left hand corner. Go ahead and go through all of your most used commands and reassign them to your own customized keyboard shortcuts.