Basic Controls

Move forward
-hold right mouse button

Use item
-left click

Take item
-left click and drag over backpack

Read books/signs
-left click

Close books/gumps
-right click

Examine item
-press and hold 'X' key when reticle is over item

Movement Controls

Run
-shift (caps lock makes run the default)

Walk to side
-hold ctrl or alt while walking

Walk backwards
-hold ctrl & alt while walking

Jump
-space bar

Swim
-right click and hold
(look up to surface; look down to dive deeper)

Climb
-'C' key

Sit or lie down
-left click on chair or bed

Inventory Controls

Open backpack
-'B' key

Hand mode (free reticle to grab items from tool belt or off self)
-'Q' key ('Q' key again goes back into normal movement mode)

Move items
-left click and drag

Equip armor and weapons
-left click and drag onto yourself

Take items
-left click and drag items onto your backpack

Close book or gump
-escape or right click

Combat Controls

Combat mode
-'Tab' key ('Tab' key again to go out of combat mode)

Attack (while in combat mode)
-left click

Attack with bow (while in combat mode)
-left click and hold to aim, release to fire arrow

Special attacks (after training)
-hold ctrl or alt while attacking

Target lock
-'T' key (press the 'N' key to cycle through nearby targets)

Defend (with shield)
-'Z' key

Magic Controls

Open Spellbook
-'S' key

Cast spell
-left click spell icon (some spells will require you to left click on a target)

Cast spells from tool belt
-left click and drag spell icon to tool belt, then use Function key or left click on spell icon to cast.

Journal

Open journal
-'J' key

Save or load game
-left click on Save/Load in your journal