All you have to do is have the spell or weapon in favorites.
Open the favorites menu and highlight your selected item with the mouse and then press 1-8.
The number will appear next to the item and will be accessible by pressing the corresponding number at any time.
1 press will get you an item in your left hand and a second will put it in the right.
Hope this helps some of you that thought the feature wasn't in the game at all. It's a but clutchy, but it works.
